Godina (Volume) 13, broj (Number) 3, Juli - Septembar (July - September)...

http://www.mf.unze.ba/masinstvo

Godina (Volume) 13, broj (Number) 3, Juli - Septembar (July - September) 2016.

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ISSN 1512-5173 http://www.mf.unze.ba/masinstvo

MAŠINSTVO ČASOPIS ZA MAŠINSKO INŽENJERSTVO

JOURNAL OF MECHANICAL ENGINEERING Godina (Volume) 13, Broj (Number) 3, Zenica, Juli – Septembar (July – September) 2016.

Uredništvo (Editorial): Fakultetska 1, 72000 Zenica Bosnia and Herzegovina Tel: +387 32 449 143; 449 145 Fax: +387 32 246 612 e-mail: [email protected] [email protected] [email protected]

Osnivač i izvršni izdavač (Founders and Executive Publisher): University of Zenica Faculty of Mechanical Engineering Fakultetska 1, 72000 Zenica Bosnia and Herzegovina Recenzioni odbor (Review committe): Dr. Safet Brdarević, Dr. Nedeljko Vukojević, Dr. Šefket Goletić, Dr. Sabahudin Ekinović

Glavni i odgovorni urednik (Editor and Chief): Prof. Dr. Sc. Safet Brdarević

Časopis izlazi tromjesečno (Journal tree monthly Urednički odbor (Editorial Board): Dr. Safet Brdarević (B&H), Dr. Jože Duhovnik (Slovenia), Dr. Vidosav Majstorović (Serbia), Dr. Milan Jurković (Croatia), Dr. Sabahudin Ekinović (B&H), Dr. Gheorge I. Gheorge (Romania), Dr. Alojz Ivanković (Ireland), Dr. Joan Vivancos (Spain), Dr. Ivo Čala (Croatia), Dr. Slavko Arsovski (Serbia), Dr. Albert Weckenman (Germany), Dr. Ibrahim Pašić (France), Dr. Zdravko Krivokapić (Montenegro), Dr. Rainer Lotzien (Germany)

Tehnički urednik (Technical Editor): Prof. Dr. Sabahudin Jašarević Štampa (Print): Štamparija Fojnica d.o.o., Fojnica Uređenje zaključeno (Preparation ended): 30.09.2016.

Časopis je evidentiran u evidenciji javnih glasila pri Ministarstvu nauke, obrazovanja, kulture i sport Federacije Bosne i Hercegovine pod brojem 651. Časopis u pretežnom iznosu finansira osnivač i izdavač. Časopis MAŠINSTVO u pravilu izlazi u četiri broja godišnje. Rukopisi se ne vraćaju

The Journal is listed under No 651 in the list of public journals in the Ministry of science, education, culture and sport of the Federation of Bosnia and Herzegovina. The Journals is mostly financed by founder and publisher. Frequency of Journal MAŠINSTVO is 4 issues a year. Manuscripts are not returned

Časopis objavljuje naučne i stručne radove i informacije od interesa za stručnu i privrednu javnost iz oblasti mašinstva i srodnih grana vezanih za područje primjene i izučavanja mašinstva. Posebno se obrađuju slijedeće tematike: - tehnologija prerade metala, plastike i gume, - projektovanje i konstruisanje mašina i postrojenja, - projektovanje proizvodnih sistema, - energija, - održavanje sredstava za rad, - kvalitet, efikasnost sistema i upravljanje proizvodnim i poslovnim sistemima, - informacije o novim knjigama, - informacije o naučnim skupovima - informacije sa Univerziteta,

The journal publishes scientific and professional papers and information of interest to professional and economic releases in mechanical engineering and related fields. In particular, the following topics are treated: - Technology for processing metal, plastic and rubber, - Design and construction of machines and plants, - The design of production systems, - Energy, - Maintenance funds for the work, - Quality and efficiency of the system and the management of production and business systems, - Information about new books, - Information about scientific meetings - Information from the University,

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RIJEČ UREDNIKA Poštovane kolegice i kolege U ovom broju Časopisa predstavljamo Vam pet radova različitog karaktera (ultrazvučna dijagnostika, upravljanje imovinom, mehanika loma, upravljanje PET ambalažom i održavanje sistema za rezanje abrazivnim vodenim mlazom). Bili smo prisustni na 22-om međunarodnom savjetovanju „ODRŽAVANJE 2016“, HDO, u Šibeniku – Hrvatska odakle Vam predstavljamo jedan rad i na 4-tom mađunarodnom naučno-stručnom skupu „ODRŽAVANJE 2016“ u Zenici, odakle Vam predstavljamo dva rada. Tu je i poziv autorima za 10-ti Međunarodni naučno-stručni skup „QUALITY 2017“ koji će se održati 17-20 maja 2017 godine u Neumu, Bosna i Hercegovina. Od laboratorija Vam predstavljamo laboratoriju LIND Zenica koja vrši ispitivanje proizvoda od drveta. Od proizvodnih firmi dobit ćete tehničko komercijalne informacije o preduzeću drvne industrije SECOM d.o.o. Visoko.

Vaš glavni i odgovorni urednikProf. emeritus dr. Safet Brdarević

EDITORIAL Dear Colleagues In this issue we present the five papers of different character (ultrasound diagnostics, asset management, fracture mechanics, management of PET packaging and maintenance of the abrasive waterjet cutting). We were attend on the 22nd International Conference "Maintenance 2016", HDO, in Šibenik - Croatia, where we bring and present a paper, and the 4-th International scientific conference "MAINTENANCE 2016" Zenica, where we present two paper. There is a call for papers for the 10th International Scientific Conference "QUALITY 2017" to be held 17-20 May 2017 years in Neum, Bosnia and Herzegovina. From the laboratory we present the laboratory LIND Zenica, which performs testing of wood products. From manufacturing companies you will get technical and commercial information is wood industry, SECOM doo Visoko.

Your editor in chiefProf. emeritus dr. Safet Brdarević

SADRŽAJ

1. Uloga ultrazvučne tehnologije u pouzdanosti H. Trobradović 139

2. Asset Management is more then just Asset Care (Maintenance): Education, Culture Change and Collaboration in Asset Life Cycle Management J. Woodhouse 155

3. Mješovitost načina loma kod simetričnih grednih uzoraka: utjecaj duljine FPZ J.Kačmarčik, P.Konjatić, A,Karač 163

4. Prijedlog sistema za upravljanje otpadnom pet ambalažom u zoni regionalne deponije „Mošćanica“ J. Sredojević, A. Ahmić 173

5. Održavanje sistema za rezanje abrazivnim vodenim mlazom S. Brdarević, A. Jeleč 185

Uputstvo za autore 196

CONTENTS

1. Ultrasound in Reliability H. Trobradović 139

2. Asset Management is more then just Asset Care (Maintenance): Education, Culture Change and Collaboration in Asset Life Cycle Management J. Woodhouse 155

3. Fracture Mode-Mixity in Symetrical Beam Specimens: FPZ Length Influence J.Kačmarčik, P.Konjatić, A,Karač 163

4. Proposal of Management PET Bottle Waste in the Zone Regional Landfill “Mošćanica” J. Sredojević, A. Ahmić 173

5. Maintenance of System for Abrasive Waterjet Cutting J. Sredojević, M. Krajšnik 57

Instruction for authors 196

Mašinstvo 2(13), 139 – 153, (2016) H.Trobradović: ULTRASOUND IN RELIABILITY

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ULOGA ULTRAZVUČNE TEHNOLOGIJE U POUZDANOSTI

ULTRASOUND IN RELIABILITY

Haris Trobradović SDT International sa.nv. Zagreb Ključne riječi: Ultrazvuk, Pouzdanost, Nadzor stanja Keywords: Ultrasound, Reliability, Condition Monitoring Paper received: 10.05.2016 Paper accepted: 13.06.2016.

Rad objavljen na konferenciji* REZIME Realnost u industriji, govoreći o pristupu održavanju u velikom broju slučajeva, u velikom je nesrazmjeru s raspoloživim znanjima i dostupnim tehnologijama. Ovakva situacija mnoge tvrtke čini nekonkurentnima ili bitno smanjuje projicirani profit. Na suvremenom globalnom tržistu, kada su resursi stabilnih ili rastućih cijena, a finalni proizvodi sve nižih cijena, budućnost se mora tražiti unutar kompanije, a održavanje u tom slučaju može i mora biti generator profita. Rast pouzdanosti se može očekivati tek kada postane nešto što se tiče svih, a ne samo tima kojem je zadatak dodijeljen. Širi pogled na dostupne tehnologije dovodi do uključivanja večeg broja zaposlenih u proces podizanja Pouzdanosti, najčešće kroz uključivanje u Nadzor stanja. Ultrazvuk u održavanju nudi širok raspon aplikacija, ali i širok raspon onih koji tehnologiju koriste, zavisno od sposobnosti i obuke.

Conference paper*

SUMMARY Reality in industry, thinking of maintenence approach in many cases, is disproportional with available technologies and knowledge. This situation is decreasing company´s competitiveness or decreasing the possible or projected profit. In the global market, when resources show stable or increasing prices, and final product price drop, future is to be found within the system, and maintenance must be a profit generator. Reliability increase can only happen once it becomes everyone's concern, not only the concern of the team in charge. Wider acceptance of available technologies inevitably leads to inclusion of larger number of employees in Reliability improvement process, most often through their participation in Condition Monitoring. Ultrasound in maintenance covers wide area of applications and wide range of employees that can use it, depending on their skills and training applied.

1. POUZDANOST I NADZOR STANJA; RASPOLOŽIVA ZNANJA I TEHNOLOGIJE NASUPROT REALNOSTI U INDUSTRIJI

Koje metode/tehnologije/alate koristite u procesu nadzoru stanja ili dijagnostici?

• Ništa ! • Vrlo jednostavne alate u vrijednosti

nižoj od 500 € • Vib, Ut (ae), Ir, Oa … sve ili nešto od

toga Da li taj dio posla za vas obavljaju vanjske tvrtke ?

• Ne ! • Ir, Vib, Oa .. u prosjeku jednom

godišnje Ova su pitanja dio svakog razgovora na temu uvođenja novih ili dodatnih tehnologija u smjeru unaprijeđenja.

1. RELIABILITY AND CONDITION MONITORING; AVAILABLE KNOWLEDGE AND TECHNOLOGIES vs REALITY IN INDUSTRY

What methods/technologies/tools you use in process of CM and diagnostics ?

• None ! • Very simple tools in value less than 500 € • Vib, Ut, Ir, Oa … all or some of it

Is that part of the job done by outsourced companies for you?

• No ! • Ir, Vib, Oa .. once a year

These questions are part of every meeting and discussion on introduction of new or additional technologies in order to achieve improvements. Answers are listed by percentage (high to low) and „None“ and „No“ keep their leading position Poredana su prema odgovorima, i prva mjesta


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zauzimaju tu poziciju vrlo čvrsto. Zasigurno se ne mogu smatrati anketom ili podacima koji predstavljaju presjek ove teme, ali u svakom slučaju mogu i trebaju izazvati zabrinutost i pogled na realnost iz jedne sasvim druge perspektive. Velika većina opreme i procesa je tretirana u „run to failure“ ((Rad do Ispada) modelu, ali ne kao dio strateške odluke zasnovane na cost/benefit analizi Prediktivnog ili Preventivnog pristupa, već kao odraz, nažalost, nemoći i degradacije u kojoj se održavanje tretira kao prvi „trošak“ koji treba „rezati“. Degradiranje struke možemo i ne moramo gledati kao na nešto tragično, ipak je kvalitetno održavanje stvar izbora, no takav stav degradira ljude, održavaoce čiji posao gubi dignitet u mnogim sredinama. Nemoguće je ne primjetiti status podmazivača, npr., čiji je posao jedno od ključnih područja u kvalitetnom održavanju. Važno je naglasiti da je ukupno raspoloživo znanje u akademskoj zajednici na vrlo visokom nivou, da je nivo kvalitete obrazovanja obzirom na prilike vrlo zadovoljavajuć, no most koji je oduvijek povezivao razvoj i primjenu je urušen ili u potpunosti nestao. Dok je važnost tog mosta u visokorazvijenim industrijama odavno prepoznata na području održavanja, u našoj se regiji desilo urušavanje ili rušenje mosta, zavisi kako na to gledamo, u posljednjih 25 godina. Shvaćanje održavanja kao neizbježnog ili nepotrebnog troška umjesto generatora profita dovodi do onoga što se ne može nazvati nikako drugačije nego anomalija s vrlo skupim i dugoročnim posljedicama. Jaz između raspoloživih znanja i realnosti primjene dovodi i do gubitka generacija koje uz formalnu edukaciju stiču iskustvo radom sa starijim kolegama, do gubitka kontinuiteta sustava u kojemu se nove tehnologije i znanja relativno lako implementiraju u manjim koracima stalne nadogradnje, te neminovno i do gubitka profita vodeći u nezaustavljivu spiralu nedostatak profita-urušavanje sustava-dodatni gubitak profita. Pod sustav moramo razumijevati ciljeve, strategije, opremu, kulturu rada i ljude. Dok su prve tri stavke skupe ali mogu biti brzo „nabavljene“, posljednje dvije su također skupe ali njihova „nabavka“ podrazumijeva mnogo vremena. Nerijetko je odgovor na ovakav slijed događaja dodatno „rezanje“ upravo tamo gdje nikako ne bi trebalo, bez dubljeg prepoznavanja gubitka koji nosi degradacija održavanja ili prepoznavanja dodatnog profita koji unaprijeđenje održavanja donosi. very strongly. And that happens in the region that

exports knowledge! This can not be considered as a scientific research or survey, but in any case can (and should) cause deep concern and change the perspective of reality. Most of the equipment and process is treated in „run to failure“ mode, but not as a part of strategic decision based on cost/benefit analysis whit in PdM or PM, but as a reflection of infirmity and degradation of maintenance where it is treated as a first „cost“ that needs to be „cut off“. We may look at degradation of profession as something tragic or not, as good maintenance practice is a matter of choice after all, but such an attitude is degrading people, maintenance people who´s work has lost dignity everywhere around us. It is impossible not to notice the status of lubrication people, „grease guy“, who´s job plays one of the most important role in modern, quality maintenance. I will strongly emphasize that available knowledge in academic society is at the very high level, that level of education quality is satisfactory (considering all), but the bridge that that was connecting technological evolution and reality in the field has collapsed or has been completely destroyed. While importance of that bridge in area of maintenance, in highly developed industries around the world, was recognized long time ago, in our region that bridge has collapsed, or has been destroyed deliberately in the past 25 years. Considering maintenance as unnecessary or inevitable cost instead of positioning it as a profit generator leads to something that can not be called by any other name but anomaly, with costly and long-term consequences. Gap between available knowledge and reality also leads to loss of generations of maintainers that, besides formal education, need to gaing experience working with more experienced colleagues, leads to loss of continuity of new technologies and approaches introduction in small, constant and easy steps, and eventually leads to unstoppable spiral of lack of profit-system collapse-additional loss of profit. By system, we need to understand all of it´s elements; goals, strategies, equipment, culture and people. While first three elements are expensive but can be „delivered“ quite fast, last two elements are not only expensive but come with enormously long delivery time. Answer to this chain of events is often making additional „cuts“ exactly where they shouldn´t be done, with no deeper understanding of the loss that maintenance degradation brings, or understanding the benefits and additional profit that it should be able to bring.


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Iz do sada navedenoga moram izuzeti određeni broj kompanija koje smatramo liderima u regiji, u kojima je situacija potpuno drugačija. Upravljanje imovinom, pouzdanost, održavanje, nadzor stanja , kultura rada i ljudi su prepoznati kao budućnost i rezultati su vrlo jasni. Te kompanije mogu služiti kao primjer, sjajan primjer, ali od samog gledanja u njih kao izvrsne primjere ne možemo očekivati rezultate. Loš pristup i neulaganje u primjenu tehnologija i potrebnih znanja donio je u velikom broju slučajeva vrlo jasne i poznate katastrofalne posljedice. Nepovratan ulazak u područje reaktivnog održavanja, visoki troškovi održavanja, propadanje opreme, neplanirani zastoj, veliki gubici energije, povećanje troškova proizvodnje i pad konkurentnosti, gubitak poslova, gubitak kvalitetnih ljudi i konačno, minorizacija uloge na trzištu koja vodi u neminovno gašenje. Znanja i tehnologije su dostupne i svakim danom sve naprednije. No, pojmovi znanje i tehnologija su neodvojivi i moraju biti dio „paketa“. U protivnom , postavlja se pitanje da li se nešto kupuje ili implementira. Uz veliki broj slučajeva kada se ne poduzima gotovo ništa, i onaj manji dio primjera kada i dođe do odluke o investiciji, ostane na kupovini i vrlo malom ili nikakvom obimu obuke. To su situacije kada tehnologija „podbaci“ i ne ispuni očekivanja. U praksi kompanija na našem području gotovo je redovna pojava da se posjeduje oprema čijih se svega 10% mogućnosti koristi. Vibrodijagnostički uređaji naprednih mogućnosti koje se koriste u rangu „vibro olovka“, Ultrazvučni uređaji koji se koriste isključivo da se locira „šištanje“, IC kamere (Infracrvene kamere) isključivo u arsenalu elektro održavanja, itd. Vjerujem da smo svi imali prilike vidjeti nevjerovatne primjere koji su samo poslužili kao razlog za eliminaciju bilo kakvih budućih investicija. Odluke o primjeni tehnologija i raspoloživih znanja leže na upravi kompanije, ali u procesu koji vodi do kvalitetne odluke je mnogo sudionika i svi moraju snositi odgovornost. Godinama potiskivani održavaoci u uvođenju novih tehnologija u svoj brojčano osakaćeni tim često vide samo novo dodatno opterećenje i stres, i time se gubi strast i želja, uz izostanak dodatne pomoći u prevladavanju implementacijskog perioda.

I need to exempt certain numbers of companies in our region from all mentioned before, companies that we consider regional leaders with completely opposite approach from what I described. Asset management, Reliability, Maintenance, Condition Monitoring, working culture and people are recognized as a future, and results are very clear. Those companies need to be an example, a great one, but nothing can be achieved just by looking at the great example. Wrong approach and poor investments in technologies and needed skills in many cases created known and very clear catastrophic consequences. Irreversible drowning in area of reactive maintenance, high maintenance costs, deterioration of equipment, high downtime, huge energy loss, increased production costs and decrease of competitiveness, loss of orders, loss of quality people and finaly, minorization of the market role that leads to inevitable eternal shut down. Knowledge and technologies are more advanced every day. But, technology and knowledge/skills are inseparable and need to be a „package“. Having technology without skills and knowledge arises a question about purchasing or implementing. With so many cases when nothing is done, even that small number of attempts of purchasing instruments stays exactly there, on purchase with none or very basic trainings and concept. Those are the situations when „technology fails“ and does not meet the expectations. Common case with companies in our region is to own instruments whose 10% of abilities is practicaly used. Advance Vibration Analysis devices used at a level of vibro pencil, Ultrasound devices used exclusively to hear air leaks „whistling“, IR Cameras exclusively in electricians toolbox, and so on. I believe that we´ve all seen incredible examples that were good for one thing only; to eliminate any future investment in maintenance. Decision about aplying technologies and available knowledge are in the domain of management, but there are many levels involved to lead to that decision, and they should all be held responsible. Mainteners, suppressed for years, can see only additional stress and workload for their maimed team, while no help and support is given during implementation period, and passion and vision soon fade away.


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U uspinjanu uz „initial hump“ (inicijalno dodatno opterećenje) večina pravih promjena i prestane postojati. U velikom broju slučajeva su očekivanja uprave potpuno nerealna i bez pravog uvida u sve potrebno za uspjeh, tražeći cjelovito rješenje u svega jednom segmentu. Iako mnoge studije napominju da udio odgovornosti odjela održavanja u unaprijeđenju pouzdanosti rijetko prelazi 20%, dramatične promjene se očekuju upravo tamo, često vjerovanjem u „čarobni štapić“ u obliku nabavljenog instrumenta. Uz neadekvatno reportiranje, projekti se ukidaju kao besmisleni i neprofitabilni. Sindrom „Ministarstva za prevenciju Zemljotresa“. Veliki broj onih koji nude tehnologije su, nažalost, „isporučioci kutija“ i isključivo trgovci opremom. To podrazumijeva trzišno ponašanje, uz dužno poštovanje naravno, i utrka za profitom nužno vodi ka prevelikim obećanjima koja su obrnuto proporcionalna pravoj podršci korisniku. Time su na gubitku svi. Luksuz takvog plasiranja tehnologije je prošlost, potrebna su cjelovita rješenja. Ponuda tehnologije mora sadržavati cijeli paket sa „zašto“, „što“ i „kako“ i korisnici se moraju naviknuti da na tome inzistiraju. Unaprijeđenje Pouzdanosti je sustav, promjena pristupa i involviranost apsolutno svih. Svojedobno je JFK rekao „Poslat ćemo čovjeka na Mjesec“ i kreirao ideju, cilj. Tijekom posjeta Nassa-inim prostorima upitao je čistača s četkom u ruci što radi.: „Šaljem čovjeka na Mjesec“. Koliko god to zvučalo senzacionalistički i kao odjavna scena filma osrednje kvalitete, zanimljivo je upitati se s koliko žara, osjećaja pripadnosti i truda je taj čovjek radio svoj posao. Pratio je cilj, bio je dio strategije, i osjećao je svoj posao kao važan. Nažalost, ponovno buđenje u realnosti. Najčešći odgovor kada se postavi pitanje o nekom problemu je bio : „To nije moj posao“. Vjerujem da to nije krivnja onoga koji je dao odgovor, već onih koji trebaju biti lideri i kreirati strategiju. Da li moraju stvoriti nešto što podsjeća na „part-time“ religiju od 07-15? Uvjeren sam da da, to rade oni koji uspješno implementiraju uspješne promjene s minimalnim sredstvima, jer u centar strategije stavljaju ljude, sve ljude od portira do generalnog managera.

Most of the real changes ceases to exist in first few steps up the „initial hump“. In most of the cases, management expectations are not realistic, without real understanding of all needed for success, while trying to have a complete solution with involvement of one single department. Although many studies show that can be held responsible for 20% of the Reliability problems, all the dramatic changes and improvements are expected to come from that department only, often through deep believe in „magical stick“ in shape of some of the CM instruments. Followed with inadequate reporting or no reporting at all, projects are canceled as meaningless or unprofitable. „Earthquake Prevention Department“ sindrom. Most of those who offer CM technologies are, unfortunately, nothing more than „box shifters“, just merchants. That is how sometimes business is percieved, with all due respect, but leads to magical promises inversely proportional to real support given to user. At the end, that makes everybody a loser. Luxury of placing technology on the market that way is a history, solutions are needed. Supply of technology, instrumments or tools means whole „package“including why, what and how and users need to become aware of the fact that they must insist on that. Reliability improvement is a system, change of approach and attitude and requires absolutely everyone to be involved. When JFK said „We choose to go to the Moon“, he created an idea, a goal that everyone felt a part of. During his visit to NASA, he approached a janitor; "Hi, I'm Jack Kennedy. What are you doing? - "Well, Mr. President," the janitor responded, "I'm helping sending a man to the Moon." However it may sound sensationalistic or like a final scene of some movie, or even being a real event or just a good marketing, it would be interesting to understand that passion, effort and sense of belonging shown by this man. He was following an idea, he was part of the strategy and he felt his job as an important part of it. Back to reality now. Most common answer when question is asked regarding some problem was; „That´s not my job“. I believe that the person who gave the answer is not to blame, but blame should be addressed to those who were supposed to be leaders and create a strategy. Do they need to create a something that has elements of „part –time“ religion? I believe yes, as that is what is done by those who successfully implement long lasting changes with minimum financial resources, by putting people in the center of their strategy, all people from doorman to general manager.


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Prije 20-tak godina smo kao imperativ vidjeli najnovije tehnologije, što je apsolutno ispravno, no zaboravljano je da je u našem poslu tehnologija samo kutija s alatom, namijenjena ljudima. Citirat ću jednog kolegu koji je nekada davno bio entuzijast, danas razočaran : „Ma kakav trening. Računovodstvo i tajnice idu na simpozije i usavršavanje svake godine, u Dubrovnik. Održavanje ne ide nigdje.“

20 years ago we set up priority in having new technologies, wich is absolutely correct, but we forgot that in our work technology is just a toolbox, ment to be used by people. I will quote one of our colleagues who once was enthusiast, now disappointed: „What training?. Accounting and secretaries have a seminar and conference in Dubrovnik, once a year. Maintenance goes nowhere“.

2. ROTIRAJU LI SVI PROBLEMI? JESU

LI TRENDIBILNI? ŠTO JE POD NADZOROM I JE LI TO DOVOLJNO?

Primarni fokus Condition Monitoringa (Nadzor Stanja) je često stavljen isključivo na rotacionu opremu, ne s punim pravom. Hidraulični i pneumatski sistemi, ventili, kavitacija u pumpama, klipna oprema, itd. Iznimno velik uticaj na pouzdanost, no nažalost često izostavljeno iz redovitog nadzora stanja. Razloga je mnogo, od tradicionalnog pogleda na kritičnost opreme, manjka ljudi ili prikladne tehnologije, do nedostatka kvalitetne analize i pripreme. Idealan omjer bi bio da je pod nadzorom sve što je financijski opravdano ili prema RPN (Risk Priority Number -Koeficijent rizika) ulazi u kritičnu ili srednje kritičnu opremu. No, opreme koja zadovoljava jedan od ova dva uvjeta je u prosjeku 80%, dok je u programu nadzora daleko manje. Naravno, govorimo o idealnim situacijama, o nečemu prema čemu treba težiti. Realnost, i sjajan korak prema povećanju pouzdanosti kroz CM (Condition Monitoring - Nadzor Stanja) je prihvaćanje različitosti tehnologija koje omogućavaju brzu „trijazu“ i uključenost večeg broja ljudi, primarno kroz Operator Driven Reliability (Uključenost Operatera u unaprijeđenje Pouzdanosti). Takva tehnologija mora omogućiti efikasnu upotrebu kroz veliki raspon raspoloživih ljudi i njihovih kompetencija i znanja. Jednostavna kada to želite, kompleksna kada je to potrebno. Upravo takvu raznolikost primjene pruža Ultrazvuk.

2. DO ALL PROBLEMS ROTATE? ARE THEY ALL TRENDIBLE? WHAT IS MONITORED AND IS THAT ENOUGH?

I will quote one of our colleagues who once was enthusiast, now disappointed: „What training?. Accounting and secretaries have a seminar and conference in Dubrovnik, once a year. Maintenance goes nowhere“. Primary focus of Condition Monitoring is usually and exclusively rotating equipment, not entirely justifiably. Hydraulics, pneumatic systems, valves, pump cavitation, reciprocating machinenry .. have the same, huge impact to Reliability, but often left out from Condition Monitoring. There are many reasons for that, from quite traditional view on equipment criticality, shortage of man power or appropriate technology, up to lack of proper analysis and work organisation. Ideal situation would be to include in Condition Monitoring everything that is financial justifiable or is highly or moderately critical regarding its RPN. But, sometimes 80% of the equipment meets criteria, and Condition Monitoring cover much less. Of course, we are talking about ideal situations, about something that we should seek for. Reality, and a great, big step towards Reliability improvement through Condition Monitoring is accepting different technologies that allow fast triage and involvement of larger number of people through Operator Driven Reliability. That technology must perform efficiently tgrough wide range of available operators and their knowledge and competences. Simple when you want it, complex when you need it. That is exactly the versatility we can find in Ultrasound.


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3. “RELIABILITY FRAMEWORK” KAO PLATFORMA PROJEKTIMA PODIZANJA POUZDANOSTI.

3. “RELIABILITY FRAMEWORK” – PLATFORM FOR RELIABILITY IMPROVEMENT PROJECTS

Slika 1. Uptime elements Figure 1. Uptime elements

Uptime Elements Reliability Framework Trade mark, (Specificirana okosnica strukovnih elemenata u unaprijeđenju Pouzdanosti organizacije ReliabilityWeb) već duže vrijeme predstavlja sjajan pregled elemenata potrebnih za uspješno unaprijeđenje pouzdanosti. 29 područja koja imaju apsolutno jednaku važnost i zaokružuju 4 temeljne grupe. Bitno je i iz ovog pregleda zaključiti već navedeno – u unaprijeđenju pouzdanosti moraju sudjelovati SVI, i to je jedini način koji garantira uspjeh. Pristup je holistički i u svojoj osnovi vrlo jednostavan. 29 „struka“ s pripadajućim pravilima i znanjima koja više ili manje nije pretjerano teško steći. No, ono što razlikuje uspješne projekte od neuspješnih je interakcija između sudionika i involviranost. Uspješan Reliability Department (Odjel za unaprijeđenje Pouzdanosti) se sastoji od SVIH zaposlenih, umreženih u strategiju, sa zajedničkim ciljem, sa zadacima koji su prilagođeni kompetencijama. Strategija koja je kreirana u izolaciji od ljudi i kulture rada koji ju trebaju izvršiti je osuđena na propast od samog početka.

„Uptime Elements Reliability Framework“ represents great overview and system of elements needed for success Reliability improvement. 29 areas that have equal importance, placed in four fundamental groups. What is important to understand, and it is visible at first glance is what was mentioned already befor – Reliability improvement involves EVERYONE, and that is the only way to have longlasting success. It is holistic approach and in its basics it shows 29 disciplines with all accompanied knowledge and rules that need to be integrated in one system. What often differentiates successful projects from less successful is interaction between stakeholders and level of involvement. Successful Reliability Department consists of all employees, networked in precise strategy, with mutual goal and tasks distributed according to competences. Strategy created in isolation from the people and work culture that is supposed to execute it is doomed from the very beginning.


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Potrebni alati i znanja su s nama odavno; Analiza vibracija od 1950-tih, Termografija od 1920-tih, FMEA (Failure Mode & Effect Analysis – Analiza oblika defekta, njihovih simptoma i efekata na proces) i RCA (Root Cause Analysis – Analiza uzroka) od 1950-tih, Ultrazvuk od 1960-tih, RCM (Reliability Centered Maintenance – Održavanje fokusirano na Pouzdanost) od 1970-tih, CMMS (Computerized Maintenance Management System) od 1960-tih …itd. Ukratko i realno, ništa novo i nepoznato i već nekoliko generacija ima pristup tim alatima. No, da li je to unaprijedilo Pouzdanost onoliko koliko je moglo i trebalo ? U pravilu ne. Primarni razlog je upravo činjenica da uspješan projekt u fokus stavlja ljude, njihovo vjerovanje u cilj, motiviranost, osjećaj pripadnosti … ali i osjećaj osobnog unaprijeđenja kroz opće unaprijeđenje. Odlučnost i vjerovanje u projekt mora biti preneseno na sve i, koliko god ta usporedba zvučala preslobodno, takav projekt svojim oblikom ima elemente religije. Kao što mnogi fitness, vegetarijanstvo, yogu ili meksičke sapunice shvaćaju gotovo kao oblik religioznog putovanja prema cilju, neshvatljivo je da se takav stav u Pouzdanosti nije stvorio u onome što je kritično za pojedinca, kompaniju i društvo u cjelini; osobni napredak pojedinca, profitabilna kompanija za stabilno društvo, održivi razvoj za čist okoliš. Ideja o projektu mora evoluirati u ideju o načinu i kulturi rada koja traje i razvija se, a kritičan element je inspirirati ljude i dati im adekvatna znanja za sudjelovanje u promjenama. Ono što osobno vidim kao primarnu prepreku da se to i ostvari je „leadership“ koji često nastupa kao Edward I iza svojih trupa, a premalo kao Leonidas. Predstavljanje 29 elemenata kao specijalističke alate (što realno i jesu) ali ne omogućiti svima da ih prihvate barem u određenoj mjeri je pogrešno, jer se time jasno odvajaju alati od onih kojima bi oni trebali služiti. Apstrahiranje vodi u nezainteresiranost i nesudjelovanje i ima dalekosežne posljedice. Pogledajmo malo manje znanstveno a malo više ljudski i osobno Uptime Elements i pouzdanost uopće. Nije li cijela ta disciplina nastala kao sistematiziran pristup onome što gotovo svi primjenjujemo u svojim domovima i svakodnevnom životu? FMEA i RCA su usađeni u naše svakodnevno ponašanje, Condition Monitoring također, KPI (Key Performance Indicators – Indikatori uspješnosti provodjenja aktivnosti) koristimo apsolutno svakodnevno iako ih tako ne nazivamo … itd.

Most of the tools have been with us for quite some time; Vibration Analysis since 50´s, Infrared Thermography since 20´s, FMEA and RCA since 50´s, Ultrasound since 60´s, RCM since 70´s, CMMS since 60´s .. and so on. In short words and realistic, nothing so new and unknown, and many generations had access to this tools. Did it really improve Reliability as much as it could have or should have ? Basicaly not. Primary reason might be the fact that successful improvement focuses on people, their belief in mutual goal, motivation, sense of belonging .. but also a perception of personal progress through success of the project. Determination and belief in the project needs to be transferred to all included and, however this might sound strange, project needs to have some elements of religion. Considering that many people take workout, fitness, vegetarianism, yoga or mexican soap operas as a kind of religious journey towards the goal, it is hard to understand that this kind of attitude was not generated in Reliability, in something so critical for each individual, for company and for sociaty in general; personal progress, profitable company for stable society, sustainable progress for clean enviroment. Idea about the project must evolve to idea about way and culture of work that lasts and develops, and critical element is to inspire people and giving them knowledge and tools necessary to be involved in changes. What I personally see as a first obstacle to make it happen is leadership that often marches behind the troops as Edward I, while it should be marching in front of them, more like Leonidas. Presenting all 29 elements as only specialistic tools (what they really are), but not bringing them closer to everyone to use them at certain level is wrong, because it strictly divides tool from those who should use them or those who have a chance to bring benefit by using them to at least certain extent. Dividing leads to disinterest and non-involvement and it has long lasting consequences. Let us look at all Reliability issue a little bit less professional, and a bit more himan end personal. Doesn´t this discipline look like a sustemized approach to what we all do in our personal life, in our family, our homes? FMEA and RCA are deeply implanted in our behaviour and life, Asset Condition Monitoring even more, KPI-s are use daily even we do not call them that way…


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Shvatimo li ih tako, i budu li tako prezentirani svima, postiže se uključenost svih, na određenom nivou. Apstrahiranje izaziva strah od nepoznatog i nerazumljivog i čini neophodne alate rezerviranima za „elitu“. Raditi više ima svoje limite, no raditi pametnije nema. Smatrao bih uspjehom kada bi se svaki lider upitao o psihološkom stanju svojih uposlenih, njihovom obiteljskom životu, entuzijazmu i u srednjoj životnoj dobi. Nekoliko globalnih kompanija je radilo istraživanje o stopi razvoda njihovih zaposlenika i usporedili su to s njihovom efikasnošću, istraživanje je obuhvatilo sve, od podmazivača do generalnog managera. Rezultat je zanimljiv, no prije svega je zanimljivo što se to netko uopće upitao. Nameće se zaključak da ključ uspjeha leži u „leadership-u“. „Leadership je umjetnost služenja drugima, pružajući im znanje, alate i ljude kao i svoje vlastito vrijeme, energiju i emocionalnu inteligenciju kako bi oni ispunili svoj puni potencijal, kako osobni, tako i profesionalni“- Daphne Mallory, , kolumnistica Entrepreneur Magazine časopisa Mislim da bi ovu definiciju trebalo kao mantru povezati s unaprijeđenjem Pouzdanosti.

Presenting Reliability tools to literally everyone in a way they can recognize the beauty, and actually recognize themselves in it will bring us absolute involment, transforming brakes to motors. Isolating generates fear of unknown and complex making necessary tools reserved exclusively for the „elite“. Working more has its limits, but working smart doesn´t. I would consider a great success if every leader would ask himself about psychological state of his employees, their personal life, family, their enthusiasm even in the autumn of their working life. Several companies did a research on divorce rate of their employees and compared it to their efficiency and progress, covering all from grease guy to CEO. Results are more than interesting, but the most important thing is that someone actually wanted to know that in a first place. So, however we look at it, the keys of success are in leader´s pocket, and leader is as good as leaders he created. “Leadership is the art of serving others by equipping them with training, tools and people as well as your time, energy and emotional intelligence so that they can realize their full potential, both personally and professionally.” according to Daphne Mallory. Make 100 people be 1% better, and it will make you be 100% better.. according to my humble self. Attitudes like „that´s not my job“ need to be part of the history.

4. ULTRAZVUK (ULTRAZVUČNA

EMISIJA); PREGLED APLIKACIJA KROZ “RELIABILITY FRAMEWORK”

Ultrazvuk, po samoj prirodi tehnologije, nalazi svoje mjesto u velikom broju Uptime Elemenata. Od jasno utemeljene uloge u nadzoru stanja, preko ODR do ljudskih potencijala i ostalih elemenata. Pojednostavljeno, razlozi su vrlo jasni; pokrivanje velikog broja aplikacija, rano otkrivanje anomalija, mogućnost upotrebe od vozača kamiona do dijagnostičara, mogućnost vrlo brze obuke za vrlo vrijedne zadatke te odličan uticaj na promjenu kulture rada. Popis aplikacija je vrlo dugačak, te ću nabrojati samo neke od njih; rotaciona oprema, podmazivanje prema realnom stanju, kavitacija u pumpama, izmjenjivači topline, hidraulični sistemi, pneumatski sistemi, električne instalacije, propuštanje instalacija pod pritiskom, parni sistemi … Lista je impresivna i omogućava iznimno veliku primjenu u svim industrijama.

4. ULTRASOUND (ULTRASONIC EMISSION); OVERVIEW OF THE APPLICATIONS ACROSS THE “RELIABILITY FRAMEWORK”

Ultrasound, by very nature of technology is involved all across the Uptime Elemenats. From clear and highly important role in Asset Condition Monitoring, through ODR, to Human Capital Management … and many others. To make it simple, reasons are very clear; Ultrasound covers waste number of applications, brings early detection of anomalies, involves everyone from specialistic diagnostic team to truck drivers, can be used for some simple but very valuable tasks even with very brief training, and it has tremendous impact to change of culture by involving many. List of applications is very long, but some of the most known are found in rotational machinery, on-condition lubrication, cavitation in pumps and valves, heat exchangers, hydraulic, pneumatics, electrical, leaks, steam systems … List is impressive and brings Ultrasound to every corner of the process in every industry.


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5. ULTRAZVUK U NADZORU; RANO OTKRIVANJE ANOMALIJA, ODR, POVEĆANJE POKRIVENOSTI NADZOROM.

Ultrazvuk nudi izuzetno vrijedan kvalitativni pomak u nadzoru stanja kroz rano otkrivanje anomalija. Ovakav pristup otvara daleko veci P-F interval (krivulja razvoja od Potencijalnog do Funkcionalnog defekta), što je ključno u kvalitetnom pristupu održavanju, ali i u povećanju pouzdanosti. Ipak, važno je naglasiti da se oprema ne ponaša uvijek onako kako teoretske analize o učestalosti i progresiji defekta govore.

5. ULTRASOUND IN ACM; EARLY DEFECT DETECTION, ODR, INCREASE IN COVERAGE

Ultrasound offers a huge qualitative improvement in ACM through early detection of anomalies. This approach opens up a wider P-F interval, giving more time to maintainers and improving Reliability. Still, it is important to understand that machinery does not always behave the way different curves ssuggest. Having usefull information just in time is a must.

Slika 2. Primjer jedne od P-F krivulja, vjerojatnost razvoja/detektibilnost

Figure 2. An example of one of the P-F curve, the likelihood of developing / detectability

U slučaju kotrljajućih ležajeva, visokofrekventni, random impakti koji karakteriziraju ranu fazu defekta se najranije i najpouzdanije otkrivaju upravo Ultrazvukom. U slučaju prenosa, situacija je gotovo ista. Kavitacija u pumpama, propuštanje ventila, stanje podmazanosti, električne instalacije.. Ultrazvuk je generiran trenjem, impactom, turbulencijom i ionizacijom, što otvara iznimne mogućnosti nadzora kroz praćenje promjena u Ultrazvučnoj emisiji.

In case or rolling elements bearings, high frequency, random impacts are characteristic of early stage of defect, and can be easily detected by Ultrasound. In case of gearboxes as well. Pump and valves cavitation, passing or blocked valves, lubrication, electrical equipment .. both improvement of detectability and improvement of inspector´s safety. Ultrasound is generated by Friction, Impacts and Turbulence and we always need to come back to that fact, not leaving it behind as something trivial.


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Gledajući pomno FMEA, upravo promjene vezane uz ova četiri fenomena nam u večini slučajeva govore iznimno mnogo. Današnji sofisticirani Ultrazvučni uređaji nude velike mogućnosti; kroz osnovne indikatore idealne za trendiranje i alarmiranje, te kroz mogućnost dublje analize dinamičkog signala, ali i kroz mogućnost „live“ donošenja zaključaka u određenim aplikacijama. Uz „prvu liniju obrane“ u procesu Condition Monitoringa, Ultrazvuk otvara iznimno velike mogućnosti u području ODR-a (Operator Driven Reliability) koji je u pravilu lakmus papir za kvalitetnu implementaciju unaprijeđenja Pouzdanosti. Kroz ODR se vrlo brzo može vidjeti koliko je uspješno kreirana atmosfera sudjelovanja svih, ka zajedničkom cilju. Takodjer, ODR, primijenjen na pravi način, efikasno i brzo mijenja navike i kulturu rada nabolje. Uzevši u obzir široko područje primjene Ultrazvuka, vrlo kratka i pouzdana mjerenja i mogućnost da neka od njih vrše i manje specijalizirano osoblje, bitno se podiže pokrivenost opreme nadzorom. Pod pojmom „prva linija obrane“, korisnici Ultrazvuka često podrazumijevaju „trijazu“; preglede opreme u potrazi za indikacijom na koju će se fokusirati specijalisti koristeći sve raspolozive metode. Ovdje je takodjer važno naglasiti da je nadzor stanja multidisciplinarni proces u kojemu ne postoji bolja ili lošija metoda, već samo oni koji su bolje ili lošije shvatili imperativ da sve raspoložive metode rade nadopunjujući jedna drugu. Kao potvrdu komplementarnosti metoda možemo posebice navesti opremu niskih okretnih brzina, gdje je Ultrazvuk nezamijenjiv kao alat.

Forgeting simple, basic things makes complex one a mistery. Looking carefully at you FMEA, changes connected to those three phenomenas are giving us priceless information. Modern, sophisticated Ultrasound devices are offering great possibilities; condition indicators ideal for trending, comparing and setting alarms, deep analysis of dynamic signal, but also ability to make „live“ decisions on spot, in certain applications, keeping it simple when it needs to be simple and fast. Besides having a role of „first line of defense“, Ultrasound opens a large opportunities in Operator Driven Reliability area that actually represents a litmus paper of implementation quality of many programs. ODR, in a matter of weeks, shows how successfully is the atmosphere of changes and involvement created. ODR, if implemented properly, changes bad habits and work culture rapidly, for better. Considering wide area of applications, short duration and reliable measurement process, as well as a possibility that they can be done by personal with some basic training, coverage increases considerably. By „first line of defense“ Ultrasound users often consider triage; inspections in search of indications that will focus specialists exactly where their valuable time needs to be spent, using Ultrasound deeply, but all other available methods as well. It cannot be emphasized enough that Asset Condition Monitoring is a multidisciplinary activity where there is no better or worse method, only people who understand their proper use or not. Different methods are not competing each other, but improving each other.

Slika 3. Rana faza promjena u ležaju Figure 3. Early phase changes in the bearing


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Slika 4. Definiran defekt, kroz repetitivne impakte

Figure 4. Defined defect, through repetitive impactor

Slika 5. Aktiviran alarm, promjena vezana uz povećano trenje Figure 5. Activated alarm, changes related to increased friction

Slika 6. Praćenje sva 4 indikatora do ispada Figure 6. Monitoring all 4 indicators to failure

6. PODMAZIVANJE PREMA REALNOM

STANJU; POTREBA, PRIMJENA I REZULTATI

Podmazivanje predstavlja ključni element koji osigurava adekvatan rad opreme. Iako je ova činjenica neupitna i deklarativno je podmazivanje istaknuto kao ključno, u praksi je to potpuno obrnuto. Podmazivanje je posao koji se često radi daleko ispod nivoa koji je potreban. Rezultati su, nažalost, vrlo porazni, ali i zanemareni jer su postali uobičajeni.

6. ON-CONDITION LUBRICATION; WHY AND HOW

Importance of lubrication does not need to be mentioned. It is known well, and declaratively mentioned as a top priority many times. On the other side, practice, it looks completely different. Declaratively most important job is actualy being done „by the way“. Results are devastating both for company and people, but not considered alarming because they became „normal“ over the years.


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Gotovo 60% ispada je uzrokovano problemima s podmazivanjem i kontaminacijom, što nije podatak koji je nov ili nepoznat. No, taj postotak je već dugo s nama i ne pokazuje tendenciju pada, jer nije došlo do promjene prakse koja takve rezultate uzrokuje. Ipak, ovakva distribucija uzročnika ispada će se shvatiti i kao dobra vijest, uzevši u obzir da se promjenom prakse u samo jednom segmentu može postići izniman napredak u Pouzdanosti.

Nerijetko je podmazivanje organizirano koristeći moto: „tako smo to radili oduvijek“, te su tako pristupi podmazivanju prema „osjećaju“, „dok mast ne izađe na drugu stranu“ ili tablice definiranog intervala podmazivanja kao jedini kriterij. Alternativa ovom pristupu je podmazivanje prema realnom stanju, „On Condition Lubrication“. Ovakav je pristup utemeljen na osnovama ovisnosti stanja podmazanosti o viskozitetu, opterećenju i brzini, ali i mnogim drugim faktorima koje je često nemoguće pretpostaviti. Uzevši u obzir Stribeck-ovu krivulju, jasno je da je područje stanja optimalne podmazanosti iznimno usko, te da sve promjene uvijek i jedino povećavaju trenje. Dok prva dva pristupa zaista ne pripadaju sadašnjosti, postavlja se pitanje i da li su vremenske tablice dovoljne, ukoliko uzmemo u obzir da su rezultat izračuna na osnovu pretpostavljenih zadanih parametara, koji se u praksi gotovo redovito mijenjaju. Uloga Ultrazvuka u ovoj aplikaciji je bazirana na činjenici da Ultrazvuk detektira i evaluira trenje i impact, što ovu tehnologiju stavlja u ključnu poziciju primarnog alata u podmazivanju. Upotrebom Ultrazvuka, primarni zadatak tima podmazivača je mjerenje, definiranje potrebe za podmazivanjem te podmazivanje uz „live“ mjerenje kako bi se odredila idealna količina.

Almost 60% of the failures are caused by lubrication and contamination of lubricant, data that is not new nor unknown. But, that percentage has been with us for quite some time and is not showing any tendency to decrease, as no practice that caused has been changed. Still, there is a very optimistic side of this distribution of causes; radical change in on, just one area of our activities can actualy bring tremendous improvement in Reliability.

Lubrication is often organized according to someone´s „feeling“, „until the grease goes out on the other side“ or using time tables as one exclusive criteria. There is a different way, proven to be better. On Condition Lubrication. This approach is considering fundamentals of level of friction and factors that influnce it; speed, load, viscosity but also factors that we can not include in theoretical calculations to determine a time interval and quantity. Considering Stribeck curve, it is clear that there is a small window, area of friction level were we would like our machinery to be, and all changes of other parameters always and only increase friction. While first two mentioned „strategies“ simply belong to history, we need to ask ourselves if time tables are enough to be trusted without any audit or adjustment, considering that parameters used to create them often and constantly change, even if the time calculation was done properly. Role of Ultrasound in this application is based on a fact that Ultrasound devices detect and evaluate friction and impact, and it is positioned in a center of lubrication strategy and used as a perfect tool to perform Acoustic Lubrication. Using Ultrasound, primary task is to measure and evaluate in order to determine weather lubrication is needed or not, and if it is .. how much, using Ultrasound „live“.


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Primjer mjerenja tokom podmazivanja na dva ležaja na istom motoru. Predefinirani režim podmazivanja je sugerirao jednaku količinu maziva u oba ležaja, u istom vremenskom intervalu. DE ležaj je trebao podmazivanje, no svega trećinu od sugerirane količine. Trenje je smanjeno na minimum.

Example of recording during the lubrication procedure on two bearings on a same shaft. Predefined lubrication regime suggested the same quantity of lubricant, same periodicly. DE bearing needed grease, but only third of suggested quantity. Friction at the minimum level.

NDE ležaj je već bio prepodmazan. Dodatno apliciranje maziva je povećalo trenje. Aplicirana je svega trećina sugerirane količine, trenje je bitno povećano.

NDE bearing was already overlubricated. Additional grease increased friction. Only one third of suggested quantity was applied.

„On condition lubrication“ uz Ultrazvuk je već etabliran pristup koji donosi izuzetno vrijedne rezultate. Prije svega kroz povećanje Pouzdanosti, eliminirajući one defekte koji svoj korijen imaju u neadekvatnom podmazivanju, ali i produzujući eksploatacijski vijek opreme. Uz to, utrošak maziva u pravilu bitno opada, što donosi dodatni financijski učinak. Tim podmazivača uz vrlo kratak trening prolazi kroz velike promjene i postaje izuzetno bitan faktor, temeljen na znanju i tehnologiji. Uz to, obavljajući svoj posao, tim podmazivača osigurava veliki broj redovnih mjerenja potrebnih za Condition Monitoring.

On-condition lubrication using Ultrasound is well established approach that brings valuable results. Primarily, through increased Reliability, by eliminating those defects caused by improper lubrication, decreasing downtime and increasing operating lifetime of assets. Besides that, most often there is a significant decrease of lubricant consumption, bringing additional financial benefit. Lubrication team, after a training and havin a proper technology, becomes a key factor, performing a job based on data and qualified decisions. Besides that, through their daily practice they provide significant quantity of measurements needed for Condition Monitoring. From doing this highly important job „by the way“, to top performance lube team is not a long journey


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7. ENERGETSKI ASPEKT, POVEĆANJE POUZDANOSTI TE SIGURNOSNI ASPEKT PRIMJENE ULTRAZVUKA

Kroz tri svakodnevne i sveprisutne aplikacije, prikazat ćemo unaprijeđenja koja upotreba Ultrazvuka donosi. 7.1. Komprimirani zrak (gubici kroz propuštanja) i parni sustav (propuštanja i „ kondenz lonci“ – korišteni vlastiti podaci) su gotovo temeljne i najjednostavnije aplikacije Ultrazvuka. Dok je obuka operatera i kvalitetna implementacija programa rada brza i jednostavna, financijski učinci su iznimno veliki. Iako svijest o magnitudi gubitaka ne postoji u onoj mjeri u kojoj je potrebno, sve je više kvalitetnih primjera onih koji su ovakvim pristupom ostvarili izuzetno velike uštede. Prema prosjecima, neinspektirani sistemi komprimiranog zraka gube i do 35%. Na primjeru dva korisnika iz naše regije, gubici od 30% su svedeni na operativne gubitke ne veće od 3%, investicija je isplaćena u 2-4 mjeseca, te su uštede dosegle iznose u jednom slučaju prezentirane na vrlo zanimljiv način; „ Ukupne mjesečne uštede su dosegle iznos dovoljan za zapošljavanje dva inženjera u odjelu održavanja, sa svim uključenim troškovima“ . Ova rečenica odražava mnogo toga što je u samim temeljima Pouzdanosti. Financijska odgovornost za uštede, socijalna odgovornost za društvo u cjelini, te briga za okoliš. 7.2. Redovit nadzor ležajeva niskih okretnih brzina te implementacija podmazivanja prema realnom stanju (korišteni vlastiti podaci) u prvoj fazi, te uključivanje i ostale opreme u proces nadzora u drugoj fazi, doveli su do smanjenja direktno vezanih troškova za 30%. Povećanje eksploatacijskog perioda i Uptime (vrijeme raspoloživosti opreme i kapaciteta) su donijeli iznimno veliku korist. Uz to, postignuta je evidentirana ušteda od prosječnih 1,5% u potrošnji električne energije nakon uvođenja podmazivanja prema stanju na elektromotorima. Projekt nije zahtijevao novo zapošljavanje, niti je rezultirao povećanim brojem radnih sati. 7.3. Uvođenje Ultrazvučnih ispitivanja u inspekcije električnih instalacija donosi unaprijeđenje u dva kritična aspekta; sigurnost inspektora i povećanje detektibilnosti. Ultrazvuk omogućava ispitivanje s većih udaljenosti i primarno ispitivanje bez otvaranja panela, što uvelike povećava sigurnost i velikim dijelom eliminira opasnost od stradanja zbog Arc Flash i Arc Blast (explozivne visokorizične pojave uzrokovane električnim lukom).

7. ENERGY SAVING, RELIABILITY INCREASE AND INCREASED SAFETY THROUGH ULTRASOUND IMPLEMENTATION

Through three usual applications of Ultrasound, we can show the benefits it brings. 7.1.Compressed air (leaks) and steam system (steam traps and steam leaks) are most common and widely present applications of Ultrasound. Operator´s training and program implementation are very fast and financial results are rapid and huge. Even though the understanding of magnitude of loses is not at the level it should be, we have more and and more examples of success in our region, and results and savings they achieved. According to international averages. Uninspected systems leak up to 35%. Two examples of users in our region are showing that loses were cut downt to 3-5% and investment returned in 2-4 months including both conpressed air and steam systems. In one of the cases, savings were presented in a very interesting way; „ Total savings reach the amount sufficient to employ two engineers in maintenance department, all expenses included“. This sentence really describes another aspect of Reliability – social responsibility and impact of each company to society in general. 7.2. Regular monitoring of low speed bearings and On-Condition lubrication implementation as a first stage and including other equipment in ACM in later stages, decreased costs by 30%. Increase of equipment lifecycle and Uptime were significant. Also, 1.5% savings in energy were achieved after introducing on-condition lubrication on electric motors. Project didn´t require new employees, or additional working hours.

7.3. Implementation of Ultrasound inspection in electrical equipment brings improvement in two critical areas; inspector safety and increased detectability. Modern Ultrasound devices allow inspector to perform inspections from the safe distance or behind closed door. Dramatically increasing safety and reducing a risk from Arc Flash and Arc Blast injury or fatality.


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5. ZAKLJUČAK Nedovoljno omasovljena primjena raspoloživih znanja i tehnologija u održavanju neminovno uzrokuje gubitke i pad konkurentnosti kompanija. Čvrsta implementacija programa podizanja Pouzdanosti je nužnost, kroz sve elemente i uz uključenost svih. Nadzor stanja, kao bitan segment Pouzdanosti može igrati ključnu ulogu ukoliko se poveča uključenost zaposlenih i pokrivenost opreme i imovine nadzorom. Ultrazvuk nudi jedno od rješenja kroz angažman u vrlo velikom broju aplikacija te mogućnost uključivanja zaposlenih na svim razinama edukacije.

6. CONCLUSION Insufficient involvement and use of technology and knowledge on all levels causes huge damage, loses and lack of competitiveness. Reliability improvement is a must, through all elements and with everyone involved. Asset Condition Monitoring, as a critically important element, plays huge role. Ultrasound is important part of solution, through waste number of applications and involvement of all levels of employees, at different levels of skills and education.

7. REFERENCES [1] Terence O´Hanlon: Certified Reliability

Leader training book, Reliabilityweb, [2] R. Keith Mobley: Maintenance

engineering handbook, 7th Edition,

Coresponding author: Haris Trobradović Area Sales & Training Manager, SDT International sa-nv Boulevard de l'Humanité 415 - 1190 Brussels - Belgium | Email: : [email protected] cell. : + 385 99 4834 882

*Rad je objavljen na IV Konferenciji „ODRŽAVANJE 2016, Zenica 02-04 juni 2016, pp. 1-10

* The paper was published in the IV Conference "MAINTENANCE 2016, Zenica 02-04 June 2016, pp. 1-10

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Mašinstvo 3(13), 155 – 161, (2016) J.Woodhouse: ASSET MANAGEMENT IS MORE…

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ASSET MANAGEMENT IS MORE THEN JUST ASSET CARE (MAINTENANCE): EDUCATION, CULTURE CHANGE AND COLLABORATION IN ASSET LIFE CYCLE MANAGEMENT

John Woodhouse Managing Director, TWPL and Chair of Expert Panel, Institute of Asset Management Keywords: Asset Management, ISO 55000, Life Cycle, Maturity, Optimisation Paper received: 26.05.2016 Paper accepted: 20.06.2016.

Conference paper* SUMMARY This paper summarizes the experiences of many organizations in migrating from an asset care (maintenance) culture to a whole life cycle asset management approach, and the benefits obtained from this transformation. It will explain the evolution of the modern discipline, and the practical steps that can be taken to break down the barriers between departments, take a long-term strategic view (instead of short-term, cost-only view) and make better risk-based decisions to justify what is worth doing, and when.

1. INTRODUCTION The accelerating growth of international interest, debate and activity in the subject of asset management is very encouraging. It is also good news that, at last, there is a converging consensus about what is needed to deliver results, but there is also an increasing variety of interpretations, flavours and misconceptions. For example, some organisations, geographical regions and industry sectors are still using "asset management" to mean just "asset maintenance". Others have recognised the bigger picture - the combination of asset design/selection/creation with the optimal blend of asset utilisation and asset care (maintenance), over the whole life cycle. We still have some challenges and education ahead, therefore, as any regular visitor to conferences, or readers of internet discussion forums, or participants in the recent ISO 55000 development1 will recognise! The different levels of capability and maturity in asset management show some consistent patterns. There are, for example, basic issues [1] that need to be acknowledged, and solutions found, before a joined-up, optimised and whole

1 ISO PC251 project that developed the first international standards for Asset Management, using

life cycle approach is viable and sustainable. These include:

1. Understanding what are the organisation's assets, and which assets have what importance (criticality), condition and capability;

2. Planning and (risk-based) decision-making processes that convert organisational objectives into 'who should do what, where, when &why'.

3. Cross-disciplinary teamwork and de-siloing of departmental motivations and selfish behaviours, to deliver best value-for-money over the whole life cycle.

4. The role, elements and integration of a management system for asset management (not to be confused with an enterprise asset information management (EAM) software tool)

2. WHAT ARE THE ASSETS, IN WHAT

CONDITION AND HOW IMPORTANTARETHEY?

Depressingly, a large number of organisations still do not even have a reasonably complete asset register. They do not know what they own. A large European rail operation discovered, a

BSI PAS 55:2008 as the basis. For more information see www.iso55000.info


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few years ago, a regional storage depot with over $200k of materials inside, that did not appear on any records at all, despite a recent 3 year data/IT initiative to update the network asset register. This is not a unique experience, even among apparently 'mature' asset management organisations. With the rate of change in technology, information systems and staff turnover, there is a constant battle to keep up to date with the basics. How up-to-date are your own 'as built' drawings, for example? Naturally there are different levels of 'granularity' in identifying and holding technical information about discrete assets (e.g. individual components, assemblies, whole equipment units, operating systems, mine s or ore bodies) but an ear1y priority must be to have a good under-standing of the primary business-enabling ("value chain") infrastructure, operational systems and supportive equipment associated with any core organisational purpose (e.g. to produce ore) or responsibility (e.g. to ensure safety). Furthermore, it is a basic expectation to have reasonable knowledge of the condition, criticality and capabilities of these assets. Yet, despite the blossoming of interest and investment in condition and performance monitoring over the last 10 years, there have been many examples of technology over-optimism and poor basic discipline, allowing data collection to be patchy and un-sustained. In many cases this is also due to lack of understanding and visibility in data usage - those collecting it do not get to see why is needed, and how it should he used. Clear understanding of the functions of the assets, and the interdependencies between them, provides a good test of asset management insight and maturity. Asset 'criticalities' are recognised to be important aids to prioritising attention and asset care, but there is still great inconsistency determination of what to use for this purpose. Some regard the consequences of failure (with safety, environmental, financial and operational impacts) as the primary concern, while others incorporate event probability or frequency to influence priorities based on levels of true risk. The leading players have even gone one stage further - since degradation and risks that change with time have such a profound impact on the appropriate timing and justification for planned intervention, it is also the rate of change in risks that needs to be identified and tracked in many cases.

3. WHO MANAGES THE ASSETS? A good asset management organisation actively works, in a coordinated way, to realise and maximise value-for-money over sustained timescales, in direct alignment with the organisation's goals. Easy to say, but this can be difficult to put into practice in a large organisation, often geographically dispersed and segmented into departmental roles and specialisms. The joined-up asset management vision requires a "total life cycle" and "total value" viewpoint: the sum of all costs, risks and benefits from initial investments (creating or acquiring assets), exploitation (usage), care (maintenance) and ultimate renewal or disposal. This presents challenges at different levels of assets integration (see figure 1). The life cyc1e management of individual equipment items is juggling act of buying the right ones, using them right, maintaining them correctly and modifying/ renewing/upgrading then appropriately. At this level of granularity there is plenty of inter-departmental tension: procurement pressure to “buy cheap” production to “sweat the assets” and maintenance concerns about risk, reliability and sustainability. At higher levels in the 'assets pyramid', system integrations 'smooth' the picture of individual activities into programmes of investment, system performance and operational activities. The business impacts are more visible and quantifiable at this level, but individual issues and 'missed opportunities' can easily be hidden in the distracting noise of budgets, conflicting departmental priorities (KPIs), politics and tribalism. More mature asset management organisations have cross-functional decision-making mechanisms that outweigh local self-interests and budget protectionism. Near the top of the pyramid, asset management attention takes the form of managing stakeholder expectations and juggling an asset portfolio to meet the conflicting demands of short- term performance and longer term security and sustained confidence. This involves a translation role, converting organisational objectives into asset management implications (and vice versa, using asset facts and realities to help manage stakeholder expectations). Unfortunately, many senior managers still use one set of wards for articulating vision, mission and goals, and then make apparent1y unrelated 'translations' into who should have what resources to do what activities in managing assets.


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Figure 1. Managing assets at different levels in a management system [2]

4. TEAMWORK IN MANAGING ASSETS Organisation structures range from largely autonomous (multi-disciplined) 'business units', to centralised, functionally specialised activities or, increasingly, a matrix combination of both. There is also a wide spectrum of approaches to what elements can or should be outsourced. Any of the extremes of independent mini-businesses or pure departmental/ functional silos, with fully in-house resources or extensively outsourced to service providers, can create difficulties for joined-up, optimised asset management (see Figure 2). Physical asset-intensive organisations, such as mining operations, are often structured by departmental specialism to a very high level, assigning separate functional responsibilities, budgets and resources to activities such as planning, engineering, procurement, operations and maintenance - and then measuring the different contributions individually and locally. These structures easily become silos, particularly if the performance measures encourage conflicting priorities. For example, capital projects/engineering functions are often targeted strongly by "on time, on budget" irrespective of operability or maintainability consequences. Similarly, asset users/operational staff seek maximum asset performance and customer service, but often at the expense of sustainable asset condition (creating the need for maintenance, yet not wanting any downtime for it).

Semi-autonomous, multi-disciplinary business units, on the other hand, easily turn in to proud, localised 'empires' that re-invent wheels, duplicate capabilities and increasingly diverge from parent organisation priorities. While the individual asset systems or business units might be more value-optimised in this model, the overall portfolio opportunities (such as adoption of common practices and sharing of 'enabler' functions or resources) can be missed. Of the two extremes, however, the establishment of a good asset management performance is most difficult within a strongly department-silo'ed organisation. The challenges lie in breaking down barriers and protectionism, reducing divisiveness in key performance indicators and even the jargon and tribalism that evolves when people only mix with others doing the same job. It is possible, however, to create an effective asset management system, even in a primarily function-based organisation, provided that cross-functional communications, decision-making and, ultimately, the measures of success have the power to outrank individual department priorities or localised performance goals. The total value-for-money card must always trump the cards of individual egos and departmental agendas. Back in the 1980's origins of modern asset management (North Sea oil & gas sector), this was achieved by creating the "culture of a small company with the leverage and resources of a large company" [4].


158

Figure 2. Actively managing the mix of functional specialisms and asset system responsibility (whole

life cycle value-for-money)

5. DECISION-MAKING At the heart of good asset management, it is often said, lies good decision-making. Yet the determination of what to do, what to spend, where and when, remains one of the commonest weaknesses in asset management. Partly this is due to lack of education (e.g. correct methods to select the best value-for-money option), partly due to lack of information (data uncertainty is inevitable) and partly due to the conflicting interests of short-term pressures versus long- term consequences, localised performance goals or resource bottlenecks. Yet research in this area [5] has shown how much is rapidly achievable, even with existing knowledge and information quality, through a little training, business discipline and "what if?" analytical tools. For example, there are 13 factors that must be considered when deciding which critical spares to hold, and in what numbers; yet the average decision-maker will usually only consider 4-5 of them. The SALVO Process [6] ensures that a more disciplined, cost/risk optimised decision is made, also creating an audit trail for why the decision is correct. Characteristics of good asset management decision-making, recognisable in leading asset management organisations, include: • fact-based (uses known-quality hard data

wherever possible and transparent, sensitivity-tested assumptions if it is not),

• risk-based (incorporate risks and uncertainties),

• considers long term as well as short term impacts (e.g. whole asset life cycle

optimization, total cost of ownership, total business impact)

• handles trade-offs between competing objectives (optimum = the best value compromise)

• uses total value-for-money as the decision criterion (not cheapest, quickest, 'technically best').

6. DATA ANALYTICS, RELIABILITY ENGINEERING & BUSINESS SKILLS A very common mistake along the path to better decisions is an over-enthusiasm for data capture and data analytics. While fact-based decision-making is highly desirable, the reality of many asset management decisions is that they:

a) are always multi-disciplinary (affecting multiple parties),

b) have to be made in the face of great uncertainties and

c) must combine (asset) technical knowledge and business context (financial and risk) information.

For example, an asset replacement decision is not just dependent upon knowledge of the current asset's past and current behaviour/condition, but also upon what is expected in future. This relates not just to the current asset's possible degradation and risks, but also the assumed characteristics of the proposed replacement (e.g. life expectancy, reliability and performance), on-going demand/criticality for the asset function, the 'cost of money' and a range of other assumptions.


159

The maturity path in this area seems to go through 3 stages:

1. Little or no data, subjective/'engineering' judgement, often driven by fire-fighting and budget allocations, little consistency & auditability,

2. Intense efforts on data collection and analytics (reporting, trending, root cause analysis etc.) in the belief that more data = better decisions (however, the reality is that more data often simply generates more confusion!).

3. Shift of focus towards business process, competencies and cross-disciplinary cost/risk evaluation methods to determine net value-for-money [6].

7. MANAGEMENT SYSTEMS FOR ASSET MANAGEMENT A "management system" is the label for whatever we put in place to ensure that what is important is identified and understood, and is converted into what gets done. It involves planning, coordination and control systems, and

a continual improvement habit at multiple levels of learning and refinement (see Figure 3). This is where there is greatest current variation in the maturity of asset management. The levels of integration and coordination range from "chaos management" environments of fire-fighting, ingenious problem-solving, short-termism and resource/budget battles, to the extremes of "command and control", where the top-down instructional and compliance culture often suppresses creativity, motivation and innovation. The optimal mix appears to be a framework of control, with a clear 'line of sight' between organisational objectives and the asset-specific management needs, in tum leading to the individual functional contributions. The controls comprise a set of common policies and agreement to adopt a common basis for risk, value definition (criticality) and prioritisation methods. Thereafter the management system is primarily focused on ensuring the vital 'enablers' of competency, data/information support and business process clarity.

Figure 3. Overwiev of an asset management system


160

8. RESULTS The outcomes of concerted efforts to better asset management, taking all these challenges into account, have been remarkable. The 'message' has spread from industry sector to sector, from the early origins in North Sea oil & gas and in the Australian public sector to power and water utilities, road, rail and air transport, petrochemical, pharmaceutical and process industries to heavy engineering, manufacturing and mining. The hard evidence of results is also emerging, and the scale of impact is greater than many would have believed possible: • CLP Hong Kong: 90% reduction in

system downtime/losses ("customer minutes lost") while reducing charged tariffs by 40% and increasing the total networklassets by 20%.

• 30% reduction in 'total cost of ownership' (Nuon electricity network)

• 30% reduction in maintenance costs with 3-10% increased availability

(mine crushing plant, Chile) • 17% increased output at 50% lower

operating cost (Shell N.Sea oil platforms) • 28% reduction in planned system

downtime (UK National Grid) • A$l1M/year budget savings (New South

Wales government) • 29% increased output at no extra cost

(Baltimore power generation).

9. CONCLUSIONS The prizes are clearly large, and the lessons share-able (the same issues, challenges and opportunities lie in most industry sectors). There are many blind alleys, however, and it is easy to slip backwards if, for example, senior managers change, or people believe that a technology-led 'solution' will solve all the problems. In each of the areas discussed, a spectrum of innocence to excellence can be identified and, in organisations that have sustained their efforts towards better asset management, a sequential path of emerging awareness, understanding, integration and optimisation found (see Figure 4). On the international stage, there is growing consensus about what comprises 'good' asset management. BSI PAS 55:2008 standard was widely accepted as a valuable catalyst to achieving such competence. Now it has moved forward to become a full ISO standard (see www.iso55000.info ) with 31 countries developing and publishing the set of 3 standards in February 2014. Casting further ahead, therefore, it is not unreasonable to expect that joined-up, cost/risk optimised, whole life cycle asset management will become a required, normal feature of all competent organisations, in the same way as safety and quality management are already.

Figure 4. IAM maturity scale for asset management


161

10. REFERENCES [1] IAM (2015), Asset Management- an

anatomy, Institute of Asset Management, www.theIAM.org

[2] PAS 55:2008, Specification for optimized management of physical assets, British Standards Institute, www.PAS55.net

[3] ISO 55000 Standard s for Asset Management, International Standards Organisation, 2014, www.ISO.org

[4] ISO 55000: Asset Management - what to do and why, John Woodhouse, ISO 2016 www.iso.org/iso/publication_item.html?pid=PUB100380

[5] SALVO project Strategic Assets: Lifecycle Value Optimisation, www.SALVOproject.org

[6] Asset Management Decision-making: the SALVO Process, John Woodhouse, TWPL 2014 www.twp1.com

Coresponding author: Managing Director, The Woodhouse Partnership Ltd (TWPL) and Chair of Experts Panel, Institute of Asset Management [email protected]

* Rad je objavljen na 22. međunarodnom savjetovanju „ODRŽAVANJE 2016, Šibenik 16-18 svibanj 2016, pp. 3-10

* The paper was published in the IV International Conference "MAINTENANCE 2016, Šibenik 16-18 May 2016, pp. 3-10


162

Mašinstvo 3(13), 163 – 171, (2016) J. Kačmarčik et al.: FRACTURE MODE-MIXITY …

163

MJEŠOVITOST NAČINA LOMA KOD SIMETRIČNIH GREDNIH UZORAKA: UTJECAJ DULJINE FPZ

FRACTURE MODE-MIXITY IN SYMETRICAL BEAM SPECIMENS:

FPZ LENGTH INFLUENCE

Josip Kačmarčik 1 Pejo Konjatić 2 Aleksandar Karač 3 1Mašinski fakultet u Zenici 2Strojarski fakultet u Slavonskom Brodu, Sveučilište Josip Juraj Strossmayer 3Politehnički fakultet u Zenici 1,3 Univerzitet u Zenici Ključne riječi: mješoviti način loma, podjela energije loma, pokusi delaminacije, model kohezivne zone, DCB-UBM pokus Keywords: mixed-mode fracture, mixed-mode partitioning, delamination tests, cohesive zone model, DCB-UBM test Paper received: 01.07.2016. Paper accepted: 08.09.2016.

Originalni naučni rad REZIME U radu se istražuje mješoviti način loma u pokusima delaminacije u kojima se koriste simetrični dvostruki konzolni uzorci opterećeni momentom savijanja. Sprovedene su MKE simulacije s primjenom modela kohezivne zone u kojima su razmatrane različite konfiguracije opterećenja pokusa i dvije vrijednosti kritične energije loma, odnosno dvije duljine zone procesa loma. Na osnovu rezultata simulacija je urađena podjela energije loma i određena mješovitost načina loma, tj. proračunati su udjeli načina I i načina II loma u ukupnoj energiji loma. Numerički određene mješovitosti načina loma za različite konfiguracije su uspoređene s rezultatima dobivenim primjenom dvije analitičke teorije podjele energije loma, koje su postavili Williams te Hutchison i Suo. Ostvarena je odlična suglasnost između numeričkih i analitičkih rezultata.

Original scientific paper

SUMMARY Mixed-mode fracture in delamination test utilizing double cantilever specimens loaded with bending moments is investigated in the paper. FEM simulations are performed using cohesive zone model where different configurations of test loadings and two critical fracture energy values, ie. two fracture process zone lengths, are considered. Fracture energy partitioning is performed and fracture mode-mixity is determined using simulation results, i.e. mode I and mode II fracture parts in total fracture energy are calculated. The fracture mode-mixities numerically determined for different configurations are compared with results obtained using two analytical fracture energy partitioning theories, according to Williams and to Hutchinson and Suo. An excellent agreement between numerical and the analytical results is observed.

1. UVOD Mnogi suvremeni materijali se prema svojoj strukturi mogu svrstati u slojevite materijale, kao npr. slojeviti kompoziti. Slojevita struktura materijala se također javlja i kod lijepljenih spojeva. Razdvajanje između slojeva, delaminacija, predstavlja jedan od najznačajnijih mehanizama loma u ovim materijalima i otpornost na delaminaciju je vrlo značajna s aspekta dizajna dijelova od slojevitih materijala.

1. INTRODUCTION Many modern materials can be classified as layered materials based on their structure, e.g. layered composites. The layered structure is also found in adhesive joints. Interlaminar separation, delamination, represents one of the most important failure modes in these materials and delamination resistance is very important from the design aspect of layered materials parts.


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Prilikom delaminacije, rast pukotine je ograničen duž ravnine sučelja između slojeva, koja predstavlja kritično mjesto u materijalu. Uslijed nemogućnosti promjene pravca rasta pukotine može doći do pojave mješovitog načina loma, tj. mogu se pojaviti različiti omjeri udjela različitih načina loma u ukupnoj energiji loma i može se dobiti mješovitost načina loma u punom opsegu, od čistog načina I do čistog načina II loma. Kako bi se poznavale točne vrijednosti lomne žilavosti pri dizajnu, potrebno je za određeni materijal poznavati krivulju loma tj. funkcionalnu ovisnost kritične energije loma GC o mješovitosti načina loma. Pored toga, razmatranje krivulje loma je značajno i kod samog dizajna i razvoja slojevitih materijala ili ljepila za različite vrste spojeva. Za ispitivanje delaminacije se koriste različiti pokusi s uzorcima u obliku greda koje se delaminacijom razdvajaju na dva kraka [1-5]. U tim pokusima lomna žilavost se mjeri kritičnom brzinom oslobađanja energije deformiranja, poznatom veličinom iz teorije Mehanike loma [6], koja se iz praktičnih razloga često naziva i energija loma. Većina pokusa delaminacije imaju konfiguraciju opterećenja u ravnini i mogu biti s čistim načinom loma I ili načinom loma II, te s njihovom mješavinom. Na osnovu eksperimentalnih rezultata takvih pokusa, tj. uopćeno rezultata mjerenja sile, pomicanja i rasta pukotine, moguće je odrediti samo ukupnu energiju loma. Kako bi se ta eksperimentalno izmjerena kritična energija loma povezala s određenom mješovitosti načina loma neophodno je napraviti podjelu energije loma na udjele od različitih načina loma. U tu se svrhu mogu primijeniti različite analitičke i numeričke metode, koje u određenim slučajevima mogu dati vrlo različite rezultate [7-13]. Dva pionirska analitička rješenja za podjelu energije loma u pokusima delaminacije, prema Williamsu [14] i Hutchinson i Suu [15], izazivala su veliko interesiranje u znanstvenoj zajednici u posljednjih 30-tak godina za ovu problematiku. Naime, ova dva rješenja daju različite rezultate za pokuse delaminacije s asimetričnim geometrijama uzoraka, što je izazvalo daljnja istraživanja i predlaganje brojnih drugih rješenja.

During delamination, a crack propagation is limited to the interface plane between layers, which represents a critical spot in a material. Due to inability of alteration of a crack propagation direction, mixed mode fracture can occur, i.e. different ratios of different fracture modes can be present in the total fracture energy and a fracture mode-mixity can be observed in a full rage, from the pure mode I to the pure mode II fracture. In order to know exact fracture toughness values in a design, it is required to determine a failure locus for a specific material, i.e. a functional dependency of critical energy fracture GC upon fracture mode-mixity. Moreover, the failure locus consideration is also important in a design and development of layered materials or adhesives for different types of joints. Different tests utilizing beam specimen separating in two arms are used for delamination testing [1-5]. In these tests, fracture toughness is measured with strain energy release rate, a known concept from Fracture mechanics [6], which is also often called fracture energy for practical reasons. Most of the delamination tests have in plane load configuration and can be with pure mode I fracture or mode II fracture and with their mix. From experimental results of these tests, i.e. generally from results of force, displacement and crack growth measurement, it is possible to determine only the total fracture energy. In order to relate the experimentally measured critical fracture energy with the specific fracture mode-mixity it is necessary to partition a fracture energy to parts from different fracture modes. For this purpose, different analytical and numerical methods can be used, which can in specific cases give very different results [7-13]. Two pioneering analytical solutions for fracture energy partitioning in delamination tests, after Williams [14] and Hutchinson and Suo [15], caused a great interest in scientific community in the last 30 years. More specifically, these two solutions give different results for delamination tests with asymmetric specimen geometries, thus initiating further research and proposals of numerous other solutions.


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Nedavno predloženo rješenje od Conroya i dr., nazvano SACA (polu-analitička kohezivna analiza; eng. semi-analytical cohesive analysis) [13, 16], u kome se, za razliku od dva pionirska rješenja, uzimaju u obzir i svojstva materijala uzorka i svojstva sučelja između slojeva definiranog modelom kohezivne zone, obećava, i čini se kako bi moglo biti rješenje ovog problema. Svojstva materijala uzorka i kohezivne zone se razmatraju preko njihovog utjecaja na duljinu zona procesa loma (eng. fracture process zone, FPZ), na osnovu jedinstvene ovisnosti mješovitosti načina loma o duljini FPZ pokazanoj u nedavnim istraživanjima ove problematike [7-13]. Pošto pokusi s asimetričnim uzorcima nisu tema ovog rada, SACA rješenje se ovdje neće detaljnije razmatrati. U ovom radu se razmatraju pokusi delaminacije sa simetričnom geometrijom uzoraka (jednake debljine krakova), za koje se dva prethodno spomenuta pionirska rješenja slažu. Primjenom pionirskih analitičkih rješenja se dobije mješovitost načina loma neovisna o svojstvima materijala uzorka i sučelja spoja između slojeva, tj. krivulja loma ovisna samo o konfiguraciji opterećenja. Cilj ovog rada je utvrditi ovu ovisnost numerički, primjenom modela kohezivne zone (CZM; eng. Cohesive zone model) u simulacijama loma (delaminacije) metodom konačnih elemenata. Za istraživanje je korišten komercijalni softver ABAQUS [17]. 2 OPIS PROBLEMA I MKE MODEL Na slici 1 je prikazana konfiguracija pokusa delaminacije koja je istraživana u radu, koja odgovara DCB-UBM pokusu (dvostuki konzolni uzorak opterećen nejednakim momentima savijanja) [18]. Radi se o simetričnom DCB uzorku, s inicijalnom pukotinom od jedne polovine ukupne duljine uzorka, kome su krakovi opterećeni momentom savijanja u različitim omjerima.

Recently suggested solution by Conroy at al, named SACA (semi-analytical cohesive analysis) [13, 16], in which, opposite to two pioneering solutions, properties of a specimen material and properties of an interface between layers defined with cohesive zone model are taken into account, is promising, and it seems that it could be the solution of this problem. Properties of a specimen material and a cohesive zone are considered by their influence on a fracture process zone (FPZ) length, based on a unique dependence of fracture mode-mixity on FPZ length, showed in the recent research of this subject [7-13]. Because the tests with asymmetrical specimens are not subject of this paper, SACA solution will not be considered here in greater detail. In this work delamination tests with the symmetrical specimen geometry (equal arm thickness) are considered, for which two aforementioned pioneering solutions agree. Fracture mode-mixity independent on properties of a specimen material and on interface between layers, i.e. a failure locus dependent only on a loading configuration, is obtained by using pioneering analytical solutions. The aim of this paper is to determine numerically this dependence, utilizing cohesive zone model (CZM) in FEM fracture (delamination) simulations. Commercial software ABAQUS is used in the research [17]. 2 PROBLEM DESCRIPTION AND FEM MODEL Fig. 1 shows the configuration of the delamination test investigated in the work, matching the DCB-UBM test (double cantilever beam specimen loaded with uneven bending moments) [18]. It is a symmetrical DCB specimen, with a pre-crack in the half of a specimen length, having its arms loaded with bending moments in various ratios.

Slika 1. Konfiguracija pokusa delaminacije Figure 1. Delamination test configuration


166

Sedam različitih vrijednosti omjera opterećenja krakova (slika 1) je razmatrano u rasponu:

0,95 1,00k = − ÷ (1) Omjer -0,95 (umjesto -1) za slučaj istog smjera momenata odabran je kako bi se izbjegao dodir površina inicijalne pukotine i potrebe za definiranjem kontakta površina u numeričkim simulacijama i dodatnim utjecajima koje bi parametri kontakta mogli unijeti u rezultate. MKE model DCB uzorka je napravljen iz dva zasebna dijela (grede), s koincidentnim čvorovima koji su povezani kohezivnim elementima nulte debljine na polovini duljine modela (isprekidana linija), dok su u drugoj polovini nepovezani i predstavljaju inicijalnu pukotinu. Na površinama inicijalne pukotine površinski kontakt nije numerički modeliran, jer se one odmah po početku pokusa rastave. Grede su modelirane s ABAQUS CPE4 (linearnim elementima s četiri čvora za ravninsko stanje deformacija), a kohezivna zona s COH2D4 elementima (kohezivnim elementima s 4 čvora). Materijal greda je linearno elastičan, izotropan, s modulom elastičnosti od 50 GPa i Poissonovim omjerom 0,38. Širenje pukotine, tj. lom, je modeliran primjenom modela kohezivne zone, gdje je model materijala definiran zakonom naprezanje-razdvajanje kojim se opisuje cijeli proces loma. Naprezanje se odnosi na veličinu sile po jedinici kohezivne površine, a razdvajanje na relativno pomicanje između dvije povezane točke u kohezivnoj zoni. Naprezanje i razdvajanje su podijeljeni u komponente u normalnom i tangentnom pravcu. Korišten je bilinearni kohezivni zakon s početnim linearno-elastičnim ponašanjem i linearnim razvojem oštećenja definiranim pomoću energije loma [19, 20]. Početno linearno-elastično ponašanje CZM je definirano s nespregnutom matricom krutosti, s proizvoljno velikom vrijednošću krutosti

15nn ss 10 PaK K= = , jednakom za oba pravca.

Inicijacija oštećenja je definirana putem kvadratnog kriterija nominalnih naprezanja:

2 2

1n so on s

t tt t

⎛ ⎞ ⎛ ⎞+ =⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ , (2)

s jednakim vrijednostima za kritičnih naprezanja u oba pravca o o o

n st t t= = .

Seven different arm loading ratios (Fig. 1) are considered in the range:

0,95 1,00k = − ÷ (1) Ratio -0,95 (instead of -1) for the case of the same moment direction is chosen to avoid contact between precrack surfaces and necessity to define the contact procedure in numerical simulations and potential additional influences on simulation results from contact parameters. The FEM model is made from two separate parts (beams) with coincident nodes connected along a half of the length (dashed line) with zero-thickness cohesive elements (having nominal thickness equal to 1). Other half of beams have unconnected coincident nodes, representing pre-crack. Surface contact on pre-crack surfaces is not numerically modelled since they are separated immediately after the test initiation. ABAQUS CPE4 (4-node bilinear plane strain quadrilateral) elements are used for modelling beams and COH2D4 (4-node two-dimensional cohesive) elements for modelling cohesive zone. The beam material is linear elastic, isotropic with the modulus of elasticity 50GPa and Poisson’s ratio 0,38. Crack propagation, i.e. fracture, is modelled using cohesive zone model, where material model is defined with a traction-separation law describing the entire fracture process. The traction refers to the force intensity divided by cohesive surface area, and the separation refers to the relative displacement between two connected points in cohesive zone. The traction and the separation have components in normal and tangential direction. A bilinear cohesive law is used with initial linear-elastic behaviour and linear damage evolution defined by fracture energy [19, 20]. The initial CZM linear-elastic behaviour is defined with uncoupled elasticity matrix, with arbitrary high set value of stiffness

15nn ss 10 PaK K= = , equal in both directions.

Element damage initiation is defined using the quadratic nominal stress criterion:

2 2

1n so on s

t tt t

⎛ ⎞ ⎛ ⎞+ =⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ , (2)

with equal critical stress values in both directions

o o on st t t= = .


167

Ukupna energija loma pri mješovitom načinu loma je definirana putem linearnog zakona:

1I IIC CI II

G GG G

⎛ ⎞ ⎛ ⎞+ =⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ , (3)

s jednakim kritičnim energijama za oba pravca (načina loma) C C C

I IIG G G= = . U istraživanju je uporabljena vrijednost interlaminarne čvrstoće od o 45 MPat = i dvije vrijednosti kritične energije loma od

C2

J200 / 3000m

G = . Iako se na taj način

razmatraju samo dvije kombinacije svojstava CZM za različite konfiguracije opterećenja (slika 1), smatralo se kako bi se drugim kombinacijama svojstava dobili ili bliski ili rezultati između rezultata dobivenih s ove dvije kombinacije. Ova pretpostavka je utemeljena na rezultatima prethodnih istraživanja autora [8, 9], u kojim je istraživana konfiguracija pokusa s opterećenjem momentom samo jednog kraka uzorka, uz razmatranje više različitih kombinacija svojstava CZM, te i asimetrične geometrije uzorka, pored simetrične. Rezultati za simetričnu konfiguraciju (konfiguracija sa k = 0, slika 1) su pokazali zanemarivu ovisnost mješovitosti načina loma o svojstvima CZM (duljini FPZ), te su u ovom radu iz praktičnih razloga za istraživanje odabrane samo dvije gore navede kombinacije svojstava CZM s kojim će se ostvariti i dvije ekstremne duljine FPZ. Kako bi se ostvario traženi odnos opterećenja momentom gornje i donje grede simulacije su izvođene u dva koraka. U prvom koraku uzorak je bio opterećen momentima u odgovarajućim omjerima koji bi doveli do stanja neposredno prije početka rasta pukotine, a u drugom koraku rast pukotine ostvarivan je rotacijom krajeva krakova grede koji su numerički modelirani kao kruta tijela (krajnja linija čvorova). Odgovarajući omjer kutova rotacije je određivan iterativno, ponavljanjem simulacija dok zadani omjer kutova rotacije ne bi ostvario i traženi omjer momenata savijanja uz prihvatljivu grešku. Opterećenje momentom savijanja je praćeno putem registracije reaktivnog momenta u čvorovima gdje je zadavana rotacija.

Total fracture energy in mixed-mode fracture is defined by a linear law:

1I IIC CI II

G GG G

⎛ ⎞ ⎛ ⎞+ =⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠ , (3)

with equal critical energies in both directions (fracture modes) C C C

I IIG G G= = . The value o 45 MPat = for interlaminar strength

and the two values C2

J200 / 3000m

G = for

critical fracture energy are used in the research. Although in this way only the two combinations of CZM properties are considered for various load configurations (Fig. 1), it is believed that other combinations would produce close results or results between those from the two combinations. This assumption is based on the results from the previous research of authors [8, 9], where the test configuration with moment loading on a single specimen arm is investigated, with consideration of various CZM parameter combinations on both asymmetrical and symmetrical specimen geometries. The results for the symmetrical configuration (configuration with k = 0, Fig. 1) showed a negligible dependence of fracture mode-mixity on CZM properties (FPZ length), and for the practical reasons only two aforementioned CZM parameter combinations are chosen here for investigation, thus providing two extreme FPZ lengths. In order to achieve a required ratio of the upper and lower beam moment loading simulations are conducted in two steps. In the first step specimen is loaded with moments in a required ratio with an intensity enough to induce the onset of preceding crack growth initiation, and in the second step crack growth is induced by rotation of beam arm ends modelled as rigid bodies (end line of nodes). An appropriate ratio of rotation angles is determined iteratively, repeating simulations until the set rotation angle ratio also generates a required moment loading ratio with an acceptable error. The bending moment loadings are monitored by registering reaction moments in the nodes where rotation is applied.


168

3 ANALITIČKA PODJELA ENERGIJE LOMA U ovom radu se razmatraju dvije pionirske, suprotstavljene teorije podjele energije loma u pokusima delaminacije – rješenja prema Wiliamsu [14] i prema Hutchinsonu i Suu [15], poznate i kao globalno i lokalno rješenje u kasnijim znanstvenim diskusijama. U oba rada je razmatran problem delaminacije u homogenoj izotropnoj gredi, debljine h, širine B, s među-lamelarnom pukotinom na udaljenostima h1 i h2 od gornje i donje površine, slika 2.

3 ANALYTICAL FRACTURE ENERGY PARTITIONING In this paper, two pioneering, confronting, fracture energy partitioning theories for delamination tests are considered – solutions by Williams [14] and by Hutchinson and Suo [15], known also as global and local solutions in later scientific discussions. In both solutions the case of delamination in homogenous isotropic beam, with height h and width B, containing an interlaminar crack at distances h1 and h2 from the top and bottom surface is considered, Fig. 2.

Slika 2. Delaminacija razmatrana u analitičkim teorijama [14] i [15]

Figure 2. Delamination considered in analytical theories [14] and [15]

Raspodjela energije loma u rješenju Williamsa napravljena je usvajanjem sljedećih (globalnih) uvjeta za deformacije i opterećenja prilikom načina I i načina II loma: - čisti način II loma dobije se ako nema normalnog razdvajanja između dva kraka, tj. ako im se elastične linije podudaraju, - čisti način I loma dobije se ako su momenti koji djeluju na dva kraka jednaki i suprotnih smjerova. Podjela energije u rješenju Hutchinsona i Sua učinjena je preko faktora intenziteta naprezanja (lokalno), izvedenih uz određena pojednostavljenja (linearnost i dimenzionalnost, prema navodima autora).

Kao što je već rečeno, primjenom ovih rješenja za asimetričnu geometriju delaminacije (h1≠h2) dobiju se različiti rezultati podjele energije. Međutim, za simetrične geometrije (h1=h2) oba rješenja daju jednake rezultate, i može se izvesti izraz za mješovitost načina loma u obliku:

( )( )

24 17 2 7

IG kG k k

++

=+

, (4)

u kome je mješovitost načina loma izražena omjerom energije vezane za način I loma u ukupnoj energiji loma.

Fracture energy partitioning in the Williams solution is done by assuming following (global) deformation and loading conditions for mode I and mode II fracture: - pure mode I fracture is obtained if there is no normal separation between two arms, i.e. there elastic lines are coincidental, - pure mode II fracture is obtained if moments acting on two arms are equal and opposite. Fracture energy partitioning in the Hutchinson and Suo solution is done using stress intensity factors (local), obtained with specific simplifications (linearity and dimensionality, according to authors).

As already mentioned, employing these solutions for asymmetrical delamination geometries (h1≠h2) different energy partitioning results are obtained. However, for symmetrical geometries both solutions give equal results, and the expression for the fracture mode-mixity can be obtained as:

( )( )

24 17 2 7

IG kG k k

++

=+

, (4)

where the fracture mode-mixity is given with the ratio of mode I fracture energy to the total fracture energy.


169

Treba uočiti da u jednadžbi (4) mješovitost način loma ovisi samo o k, odnosno omjeru intenziteta momenata savijanja koji opterećuju uzorak. Mješovitost načina loma prema jednadžbi (4) ne ovisi o svojstvima kohezivne zone niti o materijalu uzorka, što je i cilj ispitati. 4 NUMERIČKA PODJELA ENERGIJE LOMA Iako su energije vezane za način I i način II loma uključene u Abaqus jednadžbe njih nije moguće dobiti kao izlazne vrijednosti MKE analize. Zbog toga se raspodjela energije loma mora raditi numeričkim proračunom pomoću izlaznih vrijednosti naprezanja i razdvajanja. U tu svrhu se mogu primijeniti globalni [10, 21] i lokalni pristup [20, 22], koji se razlikuju u veličini kohezivne zone uključene u proračun. Kako su prethodna istraživanja pokazala da oba pristupa daju suglasne rezultate [7, 9, 12], ovdje je korišten samo globalni pristup, zasnovan na proračunu J-integrala [23]. J-integral oko pukotine se svodi na kohezivnu zonu, pa se energija vezana za način I i način II loma može odrediti pomoću izraza :

snI II

0 0

,l l

G dx G dxx x

δδσ τ∂∂

= =∂ ∂∫ ∫ , (5)

gdje je l duljina kohezivne zone u proračunu, δn i δs su normalno i tangentno razdvajanje, a σ i τ su normalna i tangentna naprezanja u kohezivnim elementima. Osa x ima pravac i smjer rasta pukotine. 4 USPOREDBA NUMERIČKIH I ANALITIČKIH REZULTATA Rezultati mješovitosti načina loma dobiveni integracijom prema jednadžbi (5), koristeći rezultate numeričkih simulacija opisanih u poglavlju 2, su uspoređeni s analitičkom krivuljom, jednadžba (4), prema rješenjima Williamsa i Hutchinsona i Sua. Usporedba je prikazana na slici 3, gdje je omjer GI/G uporabljen za definiranje mješovitosti načina loma. Usporedba pokazuje mala odstupanja između analitičkih i numeričkih rezultata, te između numeričkih rezultata dobivenih s dvije različite energije loma s kojima su ostvarene dvije različite duljine FPZ (tablica 1).

It should be noted that in Eq. (4) fracture mode-mixity is depended only on k, ie. ratio of moment intensities acting on a specimen. According to Eq. (4), fracture mode-mixity is not dependent on cohesive zone nor material properties, and the goal is to investigate it. 4 NUMERICAL FRACTURE ENERGY PARTITIONING Although mode I and mode II fracture energy partitions are included into Abaqus equations, they are not available as FEM analysis outputs. Therefore fracture energy partitioning must be performed numerically, using outputs for tractions and separations. For this purpose global [10, 21] and local approach [20, 22] can be implemented, which differ in the size of a cohesive zone included in the calculations. Since previous research showed that both approaches give agreeable results [7, 9, 12], only the global approach is used here, which is based on calculation of J-integral [23]. The J-integral around a crack is reduced to a cohesive zone and energies related to mode I and mode II fracture can be calculated with expressions:

snI II

0 0

,l l

G dx G dxx x

δδσ τ∂∂

= =∂ ∂∫ ∫ , (5)

where l is the length of integrated cohesive zone, δn and δs are normal and tangential separations, and σ and τ normal and shear stresses in cohesive elements. Axis x also coincides with a crack propagation direction. 4 COMPARISON OF NUMERICAL AND ANALYTICAL RESULTS Results of fracture mode-mixity obtained from integration with Eq. (5), using the FEM simulations described in Chapter 2, are compared with the analytical curve, Eq. (4), according to Williams and Hutchinson and Suo solutions. Fig. 3 shows the comparison, where GI/G ratio is used for fracture mode-mixity definition. Small deviations between numerical and analytical results, and also between numerical results obtained with two different fracture energies, providing two different FPZ lengths (Tab. 1), are observed.


170

Slika 3. Usporedba numeričkih i analitičkih rezultata

Figure 3. Comparison of numerical and analytical results

Tablica 1. Duljine FPZ zabilježene u MKE simulacijama Table 1. FPZ lengths registered in FEM simulations Moments ratio

Omjer momenata k

FPZ lengths for different critical fracture energies / mm Duljine FPZ za različite kritične energije loma / mm

GC=200 J/m2 GC=3000 J/m2 -0,95 2,4 11,8 -0,5 2,2 10,6

-0,25 2 9,2 0 2 8,8

0,25 1,8 6,4 0,5 1,8 5,4 1 1,6 5

5 ZAKLJUČAK Provedeno numeričko istraživanje je pokazalo vrlo malu ovisnost mješovitosti načina loma o duljini FPZ za slučaj delaminacije simetričnog grednog uzorka. Numerički rezultati se odlično slažu s dvije pionirske analitičke teorije podjele energije, prema Williamsu i prema Hutchinson i Suo, čime je potvrđena primjenljivost ovih teorija kod pokusa delaminacije sa simetričnim grednim uzorcima.

5 CONCLUSIONS The conducted numerical investigation showed very small dependence of fracture mode-mixity on a FPZ length for the case of delamination of symmetrical beam specimen. Numerical results are in excellent agreement with the pioneering analytical theories, according to Williams and Hutchinson and Suo, confirming the applicability of the theories for delamination tests with symmetrical specimens.

6 LITERATURA – REFERENCES [1] Davies P., Blackman B., Brunner A.:

Standard test methods for delamination resistance of composite materials: current status, Applied Composite Materials, 5:345-64, 1998.

[2] Harvey C. M.: Mixed-mode partition theories for one-dimensional fracture, PhD Thesis, Loughborough University, 2012.

[3] Moore D. R., Williams J. G., Pavan A.: Fracture mechanics testing methods for polymers, adhesives and composites, Elsevier, 2001.

[4] Mohan J. D.: An investigation of composite-to-composite bonding, PhD Thesis, University College Dublin, 2010.

0

0,2

0,4

0,6

0,8

1

-1 -0,75 -0,5 -0,25 0 0,25 0,5 0,75 1

GI/G

M2/M1

200

3000

Williams, Hutchinsonand Suo

GC in J/m2


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[5] Álvarez D., Blackman B. R. K., Guild J., Kinloch A. J., Taylor A. C., Osiyemi S.: Mixed-Mode Fracture in Adhesively-Bonded Joints, 36th Annual Meeting of The Adhesion Society, Hilton Daytona Beach, Daltona, USA, 2013.

[6] Anderson T. L.: FRACTURE MECHANICS: Fundamentals and Applications, CRC Press, Taylor & Francis Group, 2005.

[7] Kačmarčik J., Karač A.: Global and Local Partitioning of Energy Release Rates in FEM Simulation of FRMM Test Using Cohesive Zone, 10 th Scientific/Research Symposium with International Participation „Metallic and Nonmetallic Materials“, Bugojno, B&H, 2014.

[8] Kačmarčik J., Karač A.: Mode-Mixity in Numerical Simulation of FRMM Test: Local Partitioning using Cohesive Zone, 18th International Research/Expert Conference ”Trends in the Development of Machinery and Associated Technology”, TMT 2014, Budapest, Hungary, 2014.

[9] Kačmarčik J., Konjatić P., Karač A.: Investigation of the mixed-mode fracture in delamination tests: numerical simulations using cohesive zone and partitioning methods, Tehnicki vjesnik/Technical Gazette, 22, 2015.

[10] Conroy M., Ivankovic A., Karač A., Williams J.: Mode-Mixity In Beam-Like Geometries: Global Partitioning with Cohesive Zones, 36th Annual Meeting of The Adhesion Society, Hilton Daytona Beach, Daltona, USA, 2013.

[11] Conroy M., Sørensen B. F., Ivankovic A.: Combined Numerical and Experimental Investigation of Mode-Mixity in Beam Like Geometries, 37th Annual Meeting of The Adhesion Society, 2014.

[12] [Kačmarčik J.: Numeričko istraživanje mješovitog načina loma u pokusima delaminacije uporabom modela kohezivne zone, Doktorska disertacija, Strojarski fakultet u Slavonskom Brodu, Sveučilište Josipa Jurja Strossmayera u Osijeku, 2016.

[13] Conroy M.: Mixed Mode Fracture in Fibre Reinforced Polymer Composites, PhD Thesis, UCD Dublin, 2016.

[14] Williams J.: On the calculation of energy release rates for cracked laminates, International Journal of Fracture, 36:101-19, 1988.

[15] Hutchinson J. W., Suo Z.: Mixed mode cracking in layered materials, Advances in applied mechanics, 29:191, 1992.

[16] Conroy M., Kinloch A. J., Williams J. G., Ivankovic A.: Mixed mode partitioning of beam-like geometries: A damage dependent solution, Engineering Fracture Mechanics, 2015.

[17] Abaqus Unified FEA (v. 6.14). 6.10 ed. Providence, Rhode Island, USA: Dassault Systems Simulia Corp; 2014.

[18] Sørensen B., Jørgensen K., Jacobsen T., Østergaard R.: DCB-specimen loaded with uneven bending moments, International Journal of Fracture, 141:163-76, 2006.

[19] Abaqus. Abaqus Analysis User's Guide (v. 6.14), DassaultSystèmes, 2014.

[20] Camanho P. P., Dávila C. G.: Mixed-mode decohesion finite elements for the simulation of delamination in composite materials, NASA-Technical paper, 211737:33, 2002.

[21] Sarrado C., Turon A., Renart J., Urresti I.: Assessment of energy dissipation during mixed-mode delamination growth using cohesive zone models, Composites Part A: Applied Science and Manufacturing, 43:2128-36, 2012.

[22] Yang Q., Thouless M. D.: Mixed-mode fracture analyses of plastically-deforming adhesive joints, International Journal of Fracture, 110:175-87, 2001.

[23] Rice J. R.: A path independent integral and the approximate analysis of strain concentration by notches and cracks, Journal of applied mechanics, 35:379-86, 1968.

Coresponding author: Josip Kačmarčik University of Zenica Mechanical Engineering Faculty Email: [email protected] Phone: +387 32 449 120


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Mašinstvo 3(13), 173 – 184, (2016) J. Sredojević et al.: PROPOSAL OF MANAGEMENT …

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PRIJEDLOG SISTEMA ZA UPRAVLJANJE OTPADNOM PET AMBALAŽOM U ZONI REGIONALNE DEPONIJE „MOŠĆANICA“

PROPOSAL OF MANAGEMENT PET BOTTLE WASTE IN THE ZONE REGIONAL LANDFILL “MOŠĆANICA”

Jovan Sredojević1 Amina Ahmić2 1University of Zenica, Faculty of Mechanical Engineering 2ESTA d.o.o. Busovača Ključne riječi: PET ambalaža, upravljanje, reciklaža Keywords: PET ambalaža, upravljanje, reciklaža Paper received: xx.xx.xxxx. Paper accepted: xx.xx.xxxx.

Stručni rad REZIME Ambalažu od poli(etilen-teraftalata)(PET ambalažu) u današnjem vremenu nije moguće izbjeći, jer se koristi za pakovanje prehrambenih proizvoda i roba široke potrošnje. Nakon iskorištenje proizvoda ova ambalaža postaje otpad koji onečišćuje okoliš, zauzima veliki zapreminski prostor na deponijama i ima vrlo dug period razgradnje.Uzme li se u obzir činjenica, da se PET ambalaža može uspješno reciklirati, te ponovo dobiti ambalaža, folija, tekstil i drugi formatizirani predmeti sasvim je opravdano uspostaviti sistema upravljanja ovim otpadom. U radu su definisani uticajni faktori, na osnovu kojih je dat prijedlog realnog sistema upravljanja otpadnom PET ambalažom u zoni Regionalne deponije „Mošćanica“.

Professional Paper

SUMMARY Packaging of poly(ethylene) terephthalate (PET bottles) can not be avoided in this day and age, because it is used in food packaging and consumer goods. After utilization of the product's packaging becomes waste that pollutes the environment, occupies a large volume space in landfills and has a very long period degradation. Due to the that the PET bottles can be successfully recycled and re-get packaging, foil, textiles and other formatted cases it is justified to establish a system of managing this waste. The paper presents the influence factors that real system management of PET packaging waste at regional landfill "Moscanica"has been proposed.

1. UVOD Na današnjem nivou razvoja, ambalažu izrađenu od poli(etilen-teraftalata), PET-a, gotovo da nije moguće izbjeći. U nju je upakovan veliki broj proizvoda, uglavnom prehrambenih i roba široke potrošnje. To su: prirodna i mineralna voda, gazirani i negazirani sokovi, pivo, mlijeko, ulje, razni deterdženti, sredstva za higijenu. PET ambalaža ima široku primjenu zbog dobrih karakteristika: atraktivan izgled, dobre mehaničke osobine, povoljna cijena, mala masa, otpornost na udare i sl. Poslije potrošnje proizvoda upakovanih u PET ambalažu, ona postaje ambalažni otpad koji se u sadašnje vrijeme uglavnom odlaže zajedno sa komunalnim. Otpadna PET ambalaža onečišćuje okoliš, zauzima veliki zapreminski prostor na deponijama i ima veoma dug period razgradnje.

1. INTRODUCTION At today's level of development, packaging made of poly (ethylene-terephthalate), PET is almost impossible to avoid. A large number of products, mainly food and consumer goods are packed in it.These are: natural and mineral water, carbonated and non-carbonated juices, beer, milk, oil, various detergents, toiletries. PET packaging is widely used because of their good characteristics: an attractive appearance, good mechanical properties, good price, light weight, impact resistance and the like. After consumption of products packaged in PET containers, it becomes packaging waste that is mostly disposed together with communal. PET packaging waste pollutes the environment, occupies a large volume space in landfills and has a very long degradation.


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Za uspostavu realnog sistema upravljanja otpadnom PET ambalažom u zoni Regionalne deponije „Mošćanica“ istraženi su sljedeći uticajni faktori:

- udaljenosti općina koje, po principu regionalnosti, odlažu komunalni otpad,

- generatore i procjenu količine otpadne PET ambalaže,

- postojeće pogone i uticajne faktore na reciklažu otpadne PET ambalaže u zoni ove deponije.

The influence factors are acquire in order to the prerequisites for the planning system of PET packaging waste at regional landfill "Moscanica":

- distance of municipalities, according to the principle of regionality deposit waste at the regional landfill "Moscanica"

- Generators and estimate the amount of PET bottles waste,

- Existing facilities and influential factors on recycling PET bottles waste.

2. UDALJENOSTI OPĆINA KOJE

ODLAŽU KOMUNALNI OTPAD NA REGIONALNU DEPONIJU „MOŠĆANICA“

Regionalana deponija „Mošćanica“ locirana je na sjevernom odlagalištu površinskog kopa mrkog uglja „Mošćanica“, na udaljenosti 14 km od Zenice i predviđena je kao konačno rješenje za odlaganje otpada u regiji za narednih 30 godina. Regija iz koje se komunalni otpad odlaže na regionalnu deponiju „Mošćanica“ obuhvata općine: Žepče, Zavidovići, Zenica, Visoko, Busovača, Vitez, Travnik, Novi Travnik i Kakanj. Ukupna površina ove regije je 3107,50 km2. Prema posljednjem popisu stanovništva (2013. god) ova regija ima 395.421 stanovnika, odnosno 123.304 domaćinstava [1]. Udaljenost pojedinih općina od Regionalne deponije „Mošćanica“ iznosi: Zenica 14 km, Žepče 51,80 km, Zavidovići 68,10 km, Visoko 37,60 km, Kakanj 20 km, Busovača 21,60 km, Vitez 26,50 km, Travnik 41,40 km i Novi Travnik 41,20 km. Ekonomski opravdana granica transporta otpada određuje se na bazi stanja cestovne mreže, gustine saobraćaja i topografije terena. Iskustveni podaci pokazuju da maksimalna dužina transporta otpada klasičnim vozilima za sakupljanje otpada iznosi [2]:

- u gradskom zonama 5-10 km - u regionalnim zonama 20-25 km

2. DISTANCE MUNICIPALITIES THAT DEPOSIT WASTE TO THE REGIONAL LANDFILL "MOŠĆANICA"

Regional landfill "Moscanica" is located at the northern landfill pit mine brown coal “Moscanica", at a distance of 14 km from Zenica and is intended as a final solution for waste disposal in the region for the next 30 years. Municipality that despose waste to the regional landfill "Moscanica" are: Zepce, Zavidovici, Zenica, Visoko, Busovaca, Vitez, Travnik, Novi Travnik and Kakanj. The total area of this region is 3,107.50 km2. According to the last census (2013) in this area has 395,421 inhabitants, or 123,304 households [1]. Individual municipalities distance from regional landfill "Moscanica" is: Zenica 14 km, 51.80 km Zepce, Zavidovici 68.10 km, 37.60 km , Kakanj 20 km, Busovaca 21.60 km, 26.50 km Vitez, Travnik 41.40 km and 41.20 km Novi Travnik. Economically justifiable limit transport of waste is determined based on the state of the road network, traffic density and topography. Empirical data show that the maximum length of the waste transport with classic vehicles for waste collection is [2]: - in urban areas 5-10 km - in regional areas 20-25 km


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3. GENERATORI I PROCJENA KOLIČINE OTPADNE PET AMBALAŽE

3.1. Generatori PET ambalaže i otpadne

PET ambalaže Otpadna PET ambalaža je primarna, nepovratna i predstavlja komunalni ambalažni otpad. Produkcija otpadne PET ambalaže direktno je proporcionalna broju generatora ove amabalaže i broju generatora otpadne PET ambalaže. Generatori PET ambalaže su: proizvođači, pakeri, punioci, uvoznici distributeri, krajnji sabdjevači i trgovine, tj. oni što stavljaju ambalažu (proizvode u njoj) na tržište. Generatori otpadne otpadne PET ambalaže su krajnji korisnici proizvoda upakovanih u ovu ambalažu: domaćinstva, industrija, uslužne djelatnosti, javne ustanove, javni događaji. 3.2. Procjena količine otpadne PET

ambalaže Jedan od bitnih faktora za definisanje sistema upravljanja otpadnom PET ambalažom je njena količina. Trenutno, u nadležnim Ministarstvima Federacije BiH ne postoje podaci o količinama otpadne PET ambalaže. Jedini dostupni podaci su iz Regionalne deponije „Mošćanica“. Prema ovim podacima na deponiji je u periodu od 05.06.2008. god. do 31.12.2013. god. izdvojeno ukupno 507,64 tona otpadne PET ambalaže, a pregled po godinama dat je u tabeli 1.

3. GENERATORS AND ESTIMATED QUANTITIES PET BOTTLES WASTE

3.1. Generators PET packaging and PET bottles waste PET packaging waste is mainly primary, grants and represents municipal packaging waste. PET bottles waste production is directly proportional to the number of generators of the packaging and the number of generators of PET bottles waste. Generators PET packaging are: manufacturers, packages, fillers, importers distributors, final supplier and stores, that is those who put packaging (products in it) on the market.Generators of PET bottles waste are final-users of products packaged in this packaging: households, industry, services, public institutions, public events. 3.2. Estimated quantity of PET packaging

waste One of the important factors for defining management system PET packaging waste is its quantity. Currently, the relevant ministries there is no data on the quantities of PET bottles waste for the region of interest. The only available data are from Regional landfill "Moscanica". According to this data is allocated a total of 507.64 tons of PET bottles waste at the landfill during the period from 05.06.2008. to 31.12.2013., and review by years is given in Table 1.

Tabela 1. Količine otpadne PET ambalaže izdvojene iz komunalnog otpada na Regionalnoj deponiji „Mošćanica“ u periodu od 05.06.2008. god. do 31.12.2013. god Table 1. The quantities of PET bottles waste separated from municipal waste to the Regional landfill "Moscanica" in the period from 05.06.2008. to 31.12.2013.

No Vrsta otpada Type of waste

Godina - Year UkupnoTotal 2008. 2009. 2010. 2011. 2012. 2013.

1. PET Ambalaža (t) PET packaging (t) 15,05 64,26 83,70 133,15 123,79 87,69 507,64

Poređenjem ovih vrijednosti može se uočiti da je u 2011. godini izdvojena najveća količina. Razlog tome je donošenje „Pravilnika o ambalaži i ambalažnom otpadu“, 2011. godine. Od tada se formiraju ovlaštena preduzeća koja se bave otkupom ambalažnog otpada, kao i veliki broj neovlaštenih sakupljača, fizičkih lica, koji u ambalažnom otpadu vide materijalnu korist. Ovo dovodi do smanjenja količine otpadne PET ambalaže koja dospijeva na Regionalnu deponiju „Mošćanica“, što predstavlja veliku uštedu odlagališnog prostora.

By comparing these values can be observed that in 2011. is allocated the largest amount. The reason for this is the adoption of "Regulations on Packaging and Packaging Waste", in 2011. Since then, authorized companies are form and involved in the purchase of packaging waste, as well as a large number of unauthorized collectors, private individuals, who see tangible benefits in the packaging waste. This leads to reduced amounts of waste PET bottles, that due to the Regional landfill "Moscanica", which is a big saving landfill space.


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Referentna godina za koju je izvršena procjena produkcije otpadne PET ambalaže je 2013. Zbog nepostojanja adekvatnih podataka o količini ovog otpada, procjena je izvršena na osnovu morfološkog sastava komunalnog otpada i broja stanovnika. Za procjenu produkcije otpadne PET ambalaže uzeti su podaci morfološkog sastava komunalnog otpada iz 2011. godine (period od 24.03. do 04.04. i 22.06. do 30.06.), jer se pretpostavlja da je tada gotovo sva količina ove ambalaže završavala na Regionalnoj deponiji „Mošćanica“. (tabela 2).

The reference year for which will be assessed production waste PET bottles in 2013. Due to the lack of adequate data on the amount of waste, the assessment will be made on the basis of morphological composition of municipal waste and population. To estimate the production of PET bottles waste, the data morphological composition of municipal waste in 2011 (the period from 24.03. to 04.04. and 22.06. to 30.06.) are taken, because it is assumed that almost all the amount of packaging finishing the landfill,at that time, suspended in municipal waste (table 2).

Tabela 2. Morfološki sastav komunalnog otpada na Regionalnoj deponiji „Mošćanica“, 2011. godina Table 2. Morphological composition of municipal waste in Regional landfill "Moscanica", 2011 years

Općina Municipality

Datum uzorkova-

nja Date of

sampling

Područje Territory

Količina komunalnog

otpada u kamionu (t)

The amount of municipal waste

in the truck (t)

Veličina uzorka Sample size

Otpadna PET ambalaža

PET packaging waste

Pondesisani procenat otpadne

PET ambalaže (%)

Weighted percentage PET bottles waste (%)

Maseni udio (kg)

Mass share (kg)

Procent. udio (%)

Percent. share (%)

Maseni udio (kg) Mass share (kg)

Procent. udio (%)

Percent. share (%)

Zenica 24.03. gradsko

urban 7,4 504,86 6,82 33,9 6,72

6,68 23.06. 9,2 504,47 5,48 33,52 6,64

Žepče 31.03 gradsko i

prigradsko urban and

rural

5,32 584,76 10,99 25,24 4,32 5,00

30.06. 4,84 472,48 9,76 27,66 5,85

Visoko 29.03. gradsko i

prigradsko urban and

rural

10,49 495,08 4,72 24,94 5,04 4,07

23.06. 7,76 625,93 8,07 20,70 3,31

Busovača 04.04. gradsko

urban 10,25 529,59 5,17 35,06 6,62

6,19 27.06. 9,43 523,32 5,55 30,10 5,75

Travnik 25.03. gradsko

urban 2,61 539,32 20,66 21,54 3,99

4,50 26.06. 5,83 517,20 8,87 26,04 5,04

Nova Bila 28.03. prigradsko

rural 3,34 443,96 13,29 34,6 7,79

5,81 22.06. 3,54 471,43 13,32 18,62 3,95

Ukupno - Total: 80,01 6212,40 7,76 331,92 5,34 5,34 Procentualni udio otpadne PET ambalaže u zoni Regionalne deponije „Mošćanica“ (5,34%) treba posmatrati sa rezervom zbog toga što sastav otpada ima dinamički karakter, podložan je stalnim promjenama u zavisnosti od: veličine oblasti skupljanja, godišnjeg doba, socijalne strukture stanovništva, vrste naselja (gradsko, seosko), vrste privredne djelatnosti i dr.

The percentage share of PET bottles waste in range Regional landfill "Moscanica" (5,34%) should be viewed with caution because the composition of the waste has a dynamic character, is subject to constant change depending on: the size of the area of the collection, the season, the social structure of the population, type of settlement (urban, rural), type of economic activity and others.


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Određivanje morfološkog sastava otpada urađeno u vrijeme povećane potrošnje napitaka (proljeće, ljeto 2011.godine), uglavnom iz gradskog područja, što znatno utiče na tačnost podataka. U tabeli 3 data je procjena masenog udjela PET otpada, u komunalnom otpadu, za 2013.

godinu.Determination of morphological content of waste has done at the time of the increased consumption of beverages (spring, summer of 2011), mainly from urban areas, which significantly affect the accuracy of the data. Table 3 shows estimated weight of PET waste, municipal waste, for 2013.

Tabela 3. Procjena masenog udjela PET otpada u komunalnom otpadu za 2013. godinu Tabela 3. Procjena masenog udjela PET otpada u komunalnom otpadu za 2013. godinu

Općina Municipality

Količina komunalnog

otpada u 2013. god. (t)

The amount of municipal waste

in 2013. (t)

Procenat domaćinstava uključenih u odvoz komunalnog otpada

(%) Percentage of

households involved in municipal waste collection (%)

Broj stanovnika uključenih u odvoz komunalnog otpada

The population involved in

municipal waste collection

Procentualni udio PET otpada

(%) Percentage share

of PET waste (%)

Maseni udio PET otpada (t) Mass share of PET waste (t)

Zenica 29.085,64* 75 86.350,50 6,68 1942,92 Žepče 1.400,00** 34 10.737,88 5,00 70,00

Zavidovići 6.983,00** 35 14.095,20 5,34 372,89 Kakanj 8.774,50** 71 27.645,27 5,34 468,56 Visoko 9.208,71* 50 20.676,00 4,07 374,79

Busovača 1.143,67* 35 6.470,80 6,19 70,79 Vitez 3.360,00** 41 11.072,46 5,34 179,42

Travnik 5.758,33* 70 40.280,10 4,50 259,12 Novi Travnik 6.200,00*** 71 17.825,97 5,34 331,08

Ukupno-Total: 71.913,85 - 235.154,18 - 4069,57

*Podaci dobijeni na Regionalnoj deponiji „Mošćanica“ - Data from the regional landfill "Moscanica" **Podaci dobijeni anketiranjem komunalnih preduzeća - Data obtained by interviewing utility companies ***Podaci iz Plana upravljanja otpadom SBK/KSB za period 2015-2025 godina-Nacrt [3] - Data from the Waste Management Plan SBK / KSB for the period 2015-2025 years-draft [3] Prema podacima iz tabele 3 procjena produkcije PET otpada po stanovniku je 17,30 kg/god. Ako se u obzir uzme cjelokupno stanovništvo, procjenjuje se da u zoni Regionalne deponije „Mošćanica“ godišnje nastaje 6.840,78 tona otpadne PET ambalaže.

According to the data in Table 3 estimate of production of PET waste per capita is 17.30 kg/year. If one takes into account the entire population, it is estimated that in range Regional landfill "Moscanica" produced annually 6840.78 tons of PET bottles waste.

4. POSTOJEĆI POGONI I UTICAJNI

FAKTORI NA RECIKLAŽU OTPADNE PET AMBALAŽE

Recikliranje otpada od poli(etilen-teraftalata) jedan je od najuspješnijih i najraširenijih procesa recikliranja polimernih materijala. Recikliranje otpadne PET ambalaže može se vršiti na tri načina:

- mehaničkim postupkom (topljenjem), - hemijskim i - termičkim postupcima.

4. EXISTING FACILITIES AND INFUENCING FACTORS FOR RECYCLING PET BOTTLES WASTE

Recycling waste from poly (ethylene terephthalate) is one of the most successful and the most widespread process of recycling plastics. Recycling of PET bottles waste can be done in three ways: - mechanical process (melting) - chemical and - thermal processes.


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Mehaničkim postupcima dobiva se regranulat koji se koristi za proizvodnju novih proizvoda iste, slične ili potpuno drugačije namjene. Hemijskim i termičkim postupcima dobivaju se osnovne komponente plastičnih masa koje se koriste za proizvodnju energije. Trenutno u BiH, od navedena tri načina recikliranja primjenjuje se samo mehaničko recikliranje. Jedno od vodećih pogona za mehaničku reciklažu otpadne PET amalaže u BiH je „Omorika reciklaza“ d.o.o. Doboj, kapaciteta 400 t/mjesečno. Najveći uticaj na efikasnost mehaničke reciklaže otpadne PET ambalaže imaju sljedeći faktori: miješanje otpadne PET ambalaže sa drugim vrstama plastičnih masa, onečišćenje otpadne PET ambalaže, boja, naljepnice, tinta, ljepilo, aditivi i sl. Uslov za mehaničku preradu otpadne PET ambalaže je da se ona odvoji od drugih vrsta plastike, zbog toga je pri samom dizajniranju PET ambalaže potrebno voditi računa o mogućnosti njenog recikliranja. Miješanjem različitih vrsta otpada plastičnih masa samanjuje se kvalitet njihove reciklaže. Da bi se izvršilo što bolje selektiranje otpada plastičnih masa izvršena je standardizacija njihovog označavanja. Simboli, nazivi i skraćenice date su u tabeli 4.

Mechanical means is reprocessing which is used for production of new products of the same, similar or completely different purpose. Chemical and thermal processes receive the basic components of plastics that are used for energy production. Currently in Bosnia and Herzegovina, of the three ways of recycling applied only mechanical recycling. One of the leading drive for the mechanical recycling of PET packaging waste in BiH "Omorika reciklaža" doo Doboj, with a capacity of 400 t/month. The biggest impact on the efficiency of the mechanical recycling of PET bottles waste have the following factors: mixing the PET bottles waste from other types of plastics, contamination of PET bottles waste, color, labels, ink, adhesive, additives and the like. The requirement for mechanical processing of PET packaging waste is that it is separated from other types of plastics, because that the design of PET containers is need to take into account the possibility of its recycling. By mixing different types of plastics waste are narrowing the quality of their recycling. In order to make the best possible selection of plastics waste is made the standardization of their labeling. Symbols, names and abbreviations are given in Table 4.

Tabela 4. Simboli, nazivi i skraćenice polimera [4] Table 4. Symbols, names and abbreviations of polymer [4]

Simbol Symbol

Naziv polimera Name of polymers

Poli (etilen-tereftalat)

Poly (ethylene)

terephthalate

Polietilen visoke gustoće High-

density polyethylene

Poli (vinil-klorid)

Poly (vinyl- chloride)

Polietilen niske gustoćePoly-ethylenelow density

Poli-propilen

Poly-propylene

Poli-stiren Poly-

styrene

Ostali višeslojni materijale

Other multilayer materials

Skraćenica Abbreviation PET PE-HD PVC PE-LD PP PS -

Stepen onečišćenja, odnosno miješanje drugih vrsta otpada sa otpadom plastičnih masa direktno utiče na efikasnost njihove reciklaže. Za efikasnu (mehaničku) obadu, odnosno reciklažu, od posebnog značaja je organizacija sakupljanja ovih otpada. Od vrste i obima međusobnog miješanja otpadne PET ambalaže sa kućnim i sličnim otpadima zavisi stepen njihovog onečišćenja.

The degree of contamination or mixing other wastes from plastics waste directly affects the efficiency of their recycling. For efficient (mechanical) lunch, or recycling, of particular importance is the organization of the collection of these wastes. The type and scope of mutual interference PET bottles waste with household and similar wastes depends on their level of pollution.


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Prema porijeklu, onečišćenje otpada plastičnih masa se dijeli u dvije grupe:

- onečišćenje koje je nastalo upotrebom samog proizvoda i

- onečišćenje usljed kontakta sa drugim vrstama otpada.

5. PRIJEDLOG REALNOG SISTEMA ZA

UPRAVLJANJE OTPADNOM PET AMBALAŽOM U ZONI REGIONALNE DEPONIJE „MOŠĆANICA“

Osnovni cilj u upravljanju otpadnom PET ambalažom je što duže zadržati materijal u životnom ciklusu, a tek kod nemogućnosti daljeg mehaničkog recikliranja primjeniti hemijske i termičke postupke. Mehanička reciklaža otpadne PET ambalaže moguća je ukoliko postoji dovoljna količina čiste ambalaže, jer čišćenje poskupljuje reciklažu. Ukoliko otpadna PET ambalaža sadrži veliki stepen onečišćenja ili je u velikoj mjeri izmješana sa drugim vrstama plastike jedini način njenog korištenja je trmička obrada. Osnovne faze upravljanja otpadnom PET ambalažom su:

- sakupljanje, - transport, - sortiranje i skladištenje, - obrada i - deponovanje ostatka

Sistem upravljanja ambalažnim otpadom u Federciji Bosne i Hercegovine, zasniva se na zajedničkoj odgovornosti svih učesnika (proizvođači, uvoznici, punioci, pakeri, distributeri i krajnji snabdjevači) po principu „zagađivač plaća“. Ovo podrazumijeva da je proizvođač proizvoda odgovoran za ambalažni otpad koji nastaje nakon korištenja plasirane ambalaže na tržište. Proizvođač svoju odgovornost, odnosno obaveze, izvršava plaćanjem naknade Fondu za zaštitu okoliša ili ovlaštenom operateru, prema potpisanom ugovoru. Operater sistema je pravno lice, ovlašteno od Federalnog ministarstva okoliša i turizma, koje se bavi aktivnostima upravljanja ambalažom i ambalažnim otpadom. Operater sistema kao neprofitna organizacija sav svoj profit treba da ulaže u izgradnju infrastrukture za upravljanje ambalažnim otpadom i njegov primarni cilj je ispunjavanje zakonskih zahtjeva.

According to the origin, pollution of plastics wasteare divided into two groups:

- pollution that is caused by using the product and

- contamination due to contact with other types of waste.

5. PROPOSAL OF REAL SYSTEM

MANAGEMENT PET BOTTLES WASTE IN THE ZONE REGIONAL LANDFILL 'MOŠĆANICA"

The main objective in managing PET packaging waste is to keep the material in the life cycle as long as possible, and only with the impossibility of further mechanical recycling applied chemical and thermal processes. Mechanical recycling of PET bottles waste is possible if there is sufficient amount of clean packaging, because cleaning expensive recycling. If the PET bottles waste containing a high degree of contamination or the largely mixed with other types of plastic, thermal treatment is the only way to use. Basic phases of PET packaging waste are:

- collection, - transport, - sorting and storage, - processing and - depositing the rest. -

Packaging waste management system in the Federation of Bosnia and Herzegovina is based on the shared responsibility of all stakeholders (producers, importers, fillers, packers, distributors and final suppliers) on the principle of "polluter pays". This means that the manufacturer is responsible for the packaging waste generated after use of packaging placed on the market. Manufacturer have their responsibility, or obligation, performs payment of compensation to the Fund for Environmental Protection or an authorized operator, according to the contract signed. The system operator is a legal entity authorized by the Ministry, which deals with the activities of packaging and packaging waste. The operator of the system as a non-profit organization all their profits should invest in building infrastructure for the management of packaging waste and its primary objective is to meet the legal requirements.


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5.1. Sakupljanje otpadne PET ambalaže Da bi se otpadna PET ambalaža mogla reciklirati po sistemu „boca u bocu“ potrebno je organizovati dobre sisteme sakupljanja te edukaciju i disciplinu potrošača. Dobrom organizacijom sakupljanja otpadne PET ambalaže potrebno je postići: izdvajanje što veće količine ove ambalaže, što bolje razdvajanje otpadne PET ambalaže od drugih vrsta plastike, visok stepen čistoće i osigurati minimalne troškove transporta. Uzimajući u obzir iskustva susjednih zemalja kao i zemalja Evropske unije, preporučuje se kombinacija dva sistema skupljanja:

- sistem kontejnera na određenim lokacijama (zeleni otoci) i

- depozitni sistem. Zeleni otoci predstavljaju posebna mjesta za odvojeno prikupljanje otpada. Otpad razdvojen na mjestu nastanka se posebno odlaže u odvojene posude. Posude u okviru zelenih otoka su posebno označene za prihvat određene vrste otpada kao npr. PET ambalaža, papir, staklo i miješani komunalni otpad. Kod ovakvog načina sakupljanja postiže se nizak postotak sakupljanja, visok stepen kontaminacije od drugih vrsta otpada, miješanje otpadne PET ambalaže sa drugim vrstama plastike, visoki troškovi prevoza zbog velike zapremine u odnosu na masu. Također, u ovom slučaju potrebno je naknadno sortiranje otpadne PET ambalaže. Ovaj sistem skupljanja nije prihvatljiv za relativno čistu PET abalažu (boce od: vode, mineralne vode, sokova, mlijeka), dok je prihvatljiv za ambalažu koja treba biti podvrgnuta značajnijem čišćenju prije recikliranja kao što su boce od: deterdženata, ulja, raznih hemikalija i sl. Ovaj načina sakupljanja iziskuje realativno mala finansijska ulaganja i visok stepen ekološke svijesti građana. Najbolja motivacija za povrat otpadne PET ambalaže postiže se kroz sistem kaucije (depozita). Sistem sakupljanja funkcioniše na način da se otpadna PET ambalaža vraća na mjesto gdje je postavljen uređaj za povrat, najčešće kod distributera. Potrošač odlaže PET bocu u mašinu za povrat kaucije u kojoj se vrši skeniranje ambalaže i identificiranje pomoću bar koda, boje, marke, oblika, tj. vrši se poređenje sa podacima iz baze podataka. Ako boca nije pozitovno identificirana, nakon skeniranja, izbacuje se iz mašine i vraća potrošaču, što znači da nije iz sistema kaucije.

5.1 Collecting waste PET bottles To PET bottles waste could be recycled by the "bottle to bottle" it is necessary to organize a good collection systems and training and discipline of consumers. Good organization collecting waste PET bottles should be achieved by extraction of large quantities of waste PET bottles, extraction of large quantities of waste PET bottles, better separation of waste PET bottles from other types of plastics, a high degree of purity of waste PET bottles, ensure minimum transport costs. Taking into account the experience of neighboring countries as well as countries of the European Union, a combination of the two systems of collection are recommended:

- system container in certain locations (green islands) and

- deposit system. Green islands are special places for separate waste collection. The waste separated at source is particularly disposed in separate containers. The vessels within the green islands are specially marked to accept certain types of waste such as, PET bottles, paper, glass and mixed waste. This type of collection is achieved by a low percentage of collection, a high degree of contamination of other wastes, mixing PET bottles waste with other types of plastic, high transportation costs due to the large volume in relation to ground. Also, in this case it is necessary to subsequently sorting PET bottles waste. The collection system is not acceptable for relatively pure PET wrapping materials (bottles from water, mineral water, juice, milk), while it is acceptable for packaging that would receive significant purification before recycling such as a bottle from detergents, oils, chemicals and various. This collection method requires relativity small financial investment and a high level of environmental awareness. The best motivation for the return of PET bottles waste is achieved through a system of bail (deposit). Collection system works in a way that PET packaging waste back to the place where the device is set to return, usually at a dealer. Consumer deposited PET bottle in the machine for the return of the deposit which are scanned packaging and identification using bar code, color, brand, shape, etc., that is compared with the data from the database. If the bottle is not positively identified, after scanning, is expelled from the machine and returned to the consumer, which means that it is not the system of bail.


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Ukoliko je boca pozitivno identificirana proslijeđuje se u spremnik za sakupljanje. Ovisno od vrste uređaja, PET abalaža se može, prije skladištenja, presovati ili usitniti upotrebom određene opreme, što smanjuje zapreminu odložene ambalaže. Ovakvim sistemom prikupljanja otpadne PET ambalaže vrši se njen otkup od krajnjih korisnika. Povrat novca može se provesti na nekoliko načina: u vidu bona koji mijenja novac i može se iskoristiti u određenim prodajnim objektima ili za kupovinu određenih proizvoda, kao kupon za popust na neki proizvod, kao tiket za nagradnu igru ili donacija za dobrotvornu akciju i sl.[5] Korištenjem ovog sistema, prema iskustvu zemalja koje ga primjenjuju, ostvaruje se povrat otpadne PET abalaže i do 90 %. Depozitni sistem bi se primjenjivao za relativno čistu PET abalažu (boce od: vode, mineralne vode, sokova, mlijeka), dok bi se za ambalažu koja treba biti podvrgnuta značajnijem čišćenju prije recikliranja koristili zeleni otoci. Depozitni sistem bi se koristio uglavnom za domaćinstva, a u industrijskim objektima, uslužnim djelatnostima, javnim ustanovama i pri odvijanju javnih događaja vršilo bi se izdvajanje otpadne PET ambalaže u posebne posude, a ista bi se prodavala ovlaštenim sakupljačima. 5.2. Transport, sortiranje i skladištenje

otpadne PET ambalaže Sagledavajući, cestovnu mrežu, gustinu saobraćaja, udaljenost pojedinih općina od deponije i količinu komunalnog otpada, u regiji sa koje se otpad odlaže na Regionalnu deponiju „Mošćanica“ bilo bi opravdano formirati tri mini regije. U njima treba izgraditi pretovarne stanice sa sortirnicama. Prva mini regija obuhvatila bi Žepče i Zavidoviće, druga Kakanj i Visoko i treća Travnik, Novi Travniik i Vitez, dok bi se iz Zenice i Busovače otpad transportovao direktno na Regionalnu deponiju „Mošćanica“. 5.3. Obrada otpadne PET ambalaže Najbliže postrojenje, razmatranoj regiji, za mehaničku obradu otpadne PET ambalaže locirano je u Doboju. Ambalaža koja treba biti podvrgnuta hemijskoj ili termičkoj obradi bi se izvozila jer u Bosni i Hercegovini ne postoje ova postrojenja. Na slici 1 šematski je dat prijedlog sistema upravljanja otpadnom PET ambalažom u zoni Regionalne deponije „Mošćanica“.

If the bottle is positively identified forwards into the container for collection. Depending on the type of device, PET wrapping materials can be, before storage, calender or chop the use of certain equipment, which reduces the volume of deferred packaging. This system of collecting PET bottles waste is carried out its procurement of final users. Refunds can be done in several ways: in the form of a voucher that changing money and can be used in specific stores or for specific products, in the form of a coupon for a discount on a product, as a ticket for the prize draw, as a donation to charity, etc. [5]. Using this system, the experience of countries that apply it, and the return of waste PET wrapping materials even up to 90%. Deposit system would be applied to relatively clean PET wrapping materials (bottles of: water, mineral water, juices, milk), while the packaging, which should be subject to significant cleaning before recycling used green islands. Deposit system would be used mainly for household and industrial buildings, service sector, public institutions and with the handling of public events performed to extract the waste PET bottles in special containers, and the same would be sold to authorized collectors. 5.2. Transport, sorting and storage of PET

bottles waste Granted, road network, traffic density, distance of some municipalities of landfills and the amount of municipal waste in the region with which the waste is disposed of at the Regional landfill "Moscanica" it would be justified to form three mini region. They should build transfer stations with sorting. The first mini-region would include Zepce and Zavidovici, the second Kakanj and Visoko and third Travnik, Novi Travnik i Vitez , while the Zenica and Busovaca would transported waste directly to the Regional landfill "Moscanica". 5.3 Treatment of waste PET bottles The nearest facility, observed the region, for the mechanical treatment of waste PET bottles waste is located in Doboj. Packaging should be subjected to a chemical or thermal treatment to be exported because in Bosnia and Herzegovina there are not these plants. Figure 1 provides a proposal management system PET packaging waste in the area of Regional landfill "Moscanica".


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Slika 1. Prijedlog sistema upravljanja otpadnom PET ambalažom

u zoni Regionalne deponije „Mošćanica“ 6. ZAKLJUČAK Upravljanje ambalažnim otpadom u BiH nema značaj kakav ima u razvijenim zemljama Evrope, pogotovo kada se govori o primarnoj PET ambalaži. Selektivno izdvajanje otpadne PET ambalaže gotovo da i ne postoji. Krajnji korisnici proizvoda u PET ambalaži nemaju motiv da je odvajaju na mjestu nastanka. Predloženim sistemom upravljanja otpadnom PET ambalažom bi se najveći producenti ove ambalaže, građani, integrirali u sistem. Građani bi uvođenjem depozitnog sistema bili motivirani za povrat otpadne PET ambalaže i ne bi je, kao sada, odlagali u kontejnere komunalnog otpada, odakle mali dio ove ambalaže izdvajaju ulični sakupljači i radnici na deponiji.

6. CONCLUSION Packaging waste management in BiH does not have any significance in the developed countries of Europe, especially when it comes to the primary PET packaging. Selective separation of waste PET bottles wasteare almost non-existent. Final users of products in PET bottles have not motive to be separated at source. The proposed management system for PET packaging waste, would be the largest producers of packaging, citizens, were integrated into the system. Citizens would be motivated by the introduction of the deposit system to return PET bottles waste and not, as now, deposited in the waste container, where a small portion of the packaging stand street collectors and workers at the landfill.


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Figure 1. Proposed management system waste PET packaging in the area of Regional landfill "Moscanica" Predloženim sistemom bi se postigle:

- tehnološke prednosti (otpadna PET ambalaža je odvojena od drugih vrsta plastike, posjeduje visok stepena čistoće, odvojena po boji i smanjen joj je volumen),

- ekološke pogodnosti (valiki postotak povrata ambalaže, ušteda deponijskog prostora, štednja primarnih resursa, manja potrošnja električne energije i vode, manja emisija u zrak iz vozila za transport) i

- finansijska dobit (viša cijena čistog PET-a, manji troškovi transporta i ušteda troškova deponiranja).

-

The proposed system would be achieved by: - technological advantages (PET packaging

waste is separated from other types of plastics, has a high degree of purity, separated by color and reduced its volume),

- environmental benefits (a large percentage of return packaging, saving landfill space, saving primary resources, lower consumption of electricity and water, lower air emissions from transport vehicles) and

- financial income (higher price of pure PET, lower transport costs and cost savings of the deposit).


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7. LITERATURA – REFERENCES [1] ***(2013): Popis stanovništva,

domaćinstava/kućanstava i stanova u BiH 2013. godine preliminarni rezultati, Federalni zavod za statistiku BiH, Statistički bilten, broj:195

[2] Sredojević J.,: Obrada i deponije otpada, Univerzitet u Zenici, Mašinski fakultet, 2003.

[3] Plan upravljanja otpadom za područje Srednjobosanskog kantona/Kantona središnja Bosna za period 2015.-2025. god. – Nacrt, Institut za hidrotehniku Građevinski fakultet, Sarajevo, 2014. god.

[4] Pravilnik o obrascu, sadržaju i postupku obavještavanja o važnim karakteristikama

proizvoda i ambalaže od strane proizvođača („Službene novine FBiH“, br. 6/08)

[5] Kalambura S., Anić-Vučinić A.: Mogućnosti recikliranja PET ambalaže, Eko revija - Glasilo Fonda za zaštitu okoliša i energetsku učinkovitost, broj: 5, 2005

Coresponding author: Amina Ahmić University of Zenica Faculty of Mechanical Engineering Email: [email protected] Phone: +387 32 449 120

Mašinstvo 2(13), 185 – 195, (2016) S.Brdarević, ….: MAINTENANCE OF SYSTEM…

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ODRŽAVANJE SISTEMA ZA REZANJE ABRAZIVNIM VODENIM MLAZOM

MAINTENANCE OF SYSTEM FOR ABRASIVE WATERJET CUTTING

Safet Brdarević1 Ajdin Jeleč 1professor emeritus, University of Zenica 2ZEDA- Zenica Development Agency Ključne riječi: sistem za rezanje abrazivnim vodenim mlazom, rezne komponente, održavanje reznih komponenti. Keywords: system for abrasive waterjet cutting, cutting components, maintenance of cutting components. Paper received: 10.05.2016 Paper accepted: 13.06.2016.

Rad objavljen na konferenciji REZIME Postupak rezanja abrazivnim vodenim mlazom je prihvaćen kao efikasna tehnologija za rezanje različitih materijala. Postupak rezanja je zasnovan na kinetičkoj energiji vodenog mlaza i abrazivnih čestica koja se koristi za odnošenje materijala iz zone rezanja. Zbog erozionog kontakta između abrazivnih čestica i komponenti rezanja dolazi do oštećenja komponenti sistema za rezanje. Oštećenja navedenih komponenti prouzrokuju smanjen stepen efikasnosti i preciznosti rezanja. Kako bi se održao željeni stepen efikasnosti i preciznosti rezanja potrebno je održavati sistem za rezanje abrazivnim vodenim mlazom. Proces održavanja je zasnovan na više različitih aktivnosti čiji se vremenski interval realizovanja određuje u skladu sa intenzitetom korištenja reznih komponenti.

Conference paper

SUMMARY Abrasive waterjet cutting process is accepted effective technology for cutting various materials. Cutting process is based on kinetic energy of waterjet and abrasive particles which are used for material removal in the cutting zone. Erosional contact between abrasive particles and cutting components leads to damage in abrasive waterjet cutting system. Damages of above mentioned components cause lower cutting efficiency and precision level. To obtain the desired cutting efficiency and precision level maintenance of abrasive waterjet cutting system is needed. The maintenance process is based on various activities which realisation time interval is determined in accordance with usage intensity of cutting components.

1. OSNOVE POSTUPKA REZANJA ABRAZIVNIM VODENIM MLAZOM

Postupak obrade abrazivnim vodenim mlazom predstavlja nekonvencionalni postupak obrade koji koristi kinetičku energiju vodenog mlaza i abrazivnih čestica kao i rotaciono kretanje abrazivnih čestica za odnošenje materijala iz zone obrade odnosno realizaciju postupka rezanja. Nastanak abrazivnog vodenog mlaza je baziran na mješanju abrazivnih čestica sa vodom koja prolazi kroz uski regulator. Kretanjem vodenog mlaza velikim brzinama uz oslobađanje velike količine kinetičke energije koja se pretvara u energiju pritiska i realizuje proces rezanja. Nastali pritisak na površini predmeta obrade proizvodi mikropukotine čiji se prečnik povećava udarnim djelovanjem abrazivnih zrna. CNC sistemom upravljanja kretanja se ostvaruje posmično kretanje abrazivnog vodenog mlaza uz erodiranje materijala predmeta obrade koji se nalazu unutar zone rezanja.

1. BASICS OF ABRASIVE WATERJET CUTTING

Abrasive waterjet machining process is an nonconventional machining process which uses kinetic energy from a waterjet and abrasive particles, also it uses the rotational movement of abrasive particles for material removal from cutting zone respectively realisation of cutting process. Creation of abrasive waterjet is based on mixing abrasive particles with water which passes through a small diameter regulator. Cutting process is realised by high speed movement of waterjet that releases kinetic energy that is converted into pressure energy. Created pressure produces small cracks on workpiece surface, increasement of cracks diameter is achieved by the impact action of abrasive particles. Traverse movement of abrasive waterjet is achieved with the CNC movement system, and erosion of workpiece material located within the cutting zone.


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Navedenim načinom kretanja moguće je postići različite geometrije rezova i realizovati proces rezanja na predmetima kompleksne geometrije. Model nastanka abrazivnog vodenog mlaza predstavlja proces miješanja abrazivnih čestica i vodenog mlaza i osnovu za klasifikaciju abrazivnog vodenog mlaza. Postupak miješanja abrazivnih čestica i vodenog mlaza se može ostvariti sljedećim procesima:

• proces ubrizgavanja i • proces suspenzije.

Proces ubrizgavanja je zasnovan na fizički odvojenom dovodu vodenog mlaza veoma visokog pritiska i abrazivnih čestica i njihovom mješanju u komori za mješanje- fokusnoj cijevi unutar definisanog vremenskog intervala. Za razliku od procesa ubrizgavanja suspenzija je zasnovana na mješanju vode i abraziva i dovođenju tako pripremljene smjese u reznu glavu. Za prenos abraziva se koristi posuda pod pritiskom koja omogućava nastanak abrazivnog vodenog mlaza pri pritisku koji je znatno manji u odnosu na proces ubrizgavanja. Navedeni postupci nastanka abrazivnog vodenog mlaza predstavljaju sastavni dio sistema za rezanje abrazivnim vodenim mlazom.

With the above mentioned movement it is possible to produce cutts of different geometry and to realise the cutting process on complex geometry parts. Formation of abrasive waterjet is the mixing process of abrasives and water and presents the basics for classification of abrasive waterjet. Mixing process of abrasive particles and waterjet can be realised by following:

• injection process • suspension process

Injection process is based on physically separated supply line for high pressure waterjet and abrasive particles and mixing process inside the mixing and focusing tube in defined time intervals. Unlike injection proces, suspension process is based on mixing abrasive particles with water, and directing such prepared mixture to the cutting head. For transmission of abrasive particles a pressurized wessel is used. The vessel allows creation of abrasive waterjet under pressure that is much lower than pressure in injection process. Above mentioned processes of abrasive waterjet creation are an integral part of system for abrasive waterjet cutting.

2. OSNOVNI DIJELOVI SISTEMA ZA

REZANJE ABRAZIVNIM VODENIM MLAZOM

Komponente koje predstavljaju osnovu sistema za nastanak abrazivnog vodenog mlaza su: • pumpa visokog pritiska- omogućava nastanak

vodenog mlaza veoma visokog pritiska, • zglobna rezna glava- višeosnost rezne glave

omogućava rezanje pod definisanim uglom i automatsko smanjenje konusa za ostvarenje preciznih vertikalnih rezova,

• mlaznica- omogućava povećanje pritiska abrazivnog vodenog mlaza i centrifugalno kretanje abrazivnih čestica po obodu vodenog mlaza,

• rezervoar za skupljanje abraziva i odnešenog materijala tokom rezanja- omogućava apsorpciju energije abrazivnog vodenog mlaza,

• rezervoar za abrazivni materijal- omogućava kontrolirani i kontinuirani protok abrazivnih čestica kroz mlaznicu,

• x-y sistem kretanja- omogućava realizaciju posmičnog kretanja rezne glave i

• PC zasnovan kontroler- omogućava CNC upravljani sistem procesa rezanja.

2. BASIC PARTS OF SYSTEM FOR ABRASIVE WATERJET CUTTING

Components that present the basics of the system for creation of abrasive waterjet are: • high pressure pump- allows creation of high

pressure water jet • articulated cutting head- multi axis cutting

head permits allows cuts under defined angles and automatically minimization of taper for precise vertical cuts.

• abrasive waterjet nozzle- allows increasement of abrasive waterjet pressure and centrifugal movement of abrasive particles around perimeter of waterjet.

• catcher tank- allows absorption of abrasive waterjet energy

• abrasive hopper- allows controlled and continuous flow of abrasive particles trough abrasive waterjet nozzle

• x-y traverse system- allows realisation of traverse movement of abrasive waterjet cutting head

• PC based controller- allows CNC contorolled cutting process


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Slika 1. Osnovne komponente OMAX sistema za rezanje abrazivnim vodenim mlazom [1]

Figure 1. Basic components of OMAX abrasive waterjet cutting system [1] 2.1. Sistem za generisanje visokog pritiska (pumpa sa visokim pritiskom) Sistem za generisanje vodenog mlaza veoma visokog pritiska čine dva osnovna oblika hidrauličnih pumpi:

• hidraulična pumpa sa radilicom i • hidraulična pumpa sa pojačivačima.

Radilica sa minimalno tri klipa povezana sa elektromotorom predstavlja osnovu hidraulične pumpe sa radilicom. Obrtnim kretanjem radilice nastalog radom električnog motora se omogućava naizmjenično kretanje klipova- višetaktni rad kojim se postiže pravovremeno usisavajne i potiskivanje vode kroz cilindre. Kretanje vode kroz cilindre se ostvaruje uz postepeno povećanje njenog pritiska. Navedene pumpe se zbog fluktuacija pritiska ne primjenjuju za postizanje malih pritisaka. Za nastanak visokih pritisaka koriste se hidraulične pumpe sa pojačivačima zasnovane na hidrauličnoj tečnosti koja pomjera veliki naizmjenično pokretni klip. Kretanjem tog klipa se istovremeno vrši kretanje malih bočnih klipova koji usisavaju i potiskuju vodu kroz lijevi i desni radni cilindar.

2.1. System for generation of high pressure (high pressure pump) System for generation of high pressure waterjet consists of two types of hydraulic pumps:

• hydraulic pump with crankshaft and • hydraulic pump with intensifier.

Crankshaft with minimum three pistons is connected with electric motor that presents the basic for the hydraulic pump. With rotational movement of the crankshaft created by the electric motor alternating movement of pistons is enabled- multi stroke movement that is used to obtain suction and suppression of water trough cylinders. Movement of water trough cylinders is accomplished with increasement of water pressure. Because of pressure fluctuation these pumps are not used for production of high pressure. Hydraulic pumps with intensifiers are used for production of high pressures. These pumps use hydraulic fluid for movement of the big alternate movig piston. With movement of that piston smaller side pistons move simultaneously, these piston suck and suppress water trough left and right work cylinder.


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Slika 2. Shematski prikaz hidraulične pumpe sa radilicom i sa pojačivačima [1][4].

Figure 2. Schematic view of hydraulic pumps with crankshaft and intensifier [1][4].

2.2. Rezna glava Rezna glava predstavlja komponentu obradnog sistema koja direktno utiče na efikasnost i mogućnost rezanja predmeta velikih debljina. Prolaskom vodenog mlaza kroz reznu glavu i primjenom mlaznice se postiže njegovo centriranje i sprječava proširenje izlaznog prečnika.

2.2 Abrasive waterjet cutting head Abrasive waterjet cutting head presents the component of machining system that directly affects efficiency and possibility to cut tick objects. With passage of waterjet trough cutting head and application of a nozzle its centering is achieved, and with that widening of the output diameter is eliminated.

Slika 3. Shematski prikaz rezne glava i modela miješanja abrazivnih čestica i vodenog mlaza [1][3] Figure 3. Schematic view of cutting head and abrasive particles and waterjet mixing model [1][3]


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2.3. Rezervoar za skupljanje abraziva i odnešenog materijala tokom procesa rezanja Nakon prolaska abrazivnog vodenom mlaza kroz predmet obrade on i dalje sadrži znatnu količinu kinetičke energije koja može prouzrokovati oštaćenja obradne mašine. Također abrazivne čestice zbog erozione interakcije sa predmetom obrade gube određenu količinu energije. Navedeni gubitak energije neznatan u odnosu na ukupnu količinu kinetičke energije mlaza koji je prošao kroz predmet obrade. Neophodnost za apsorpcijom navedene kinetičke energije rezultira primjenom rezervoara za sakupljanje abraziva i odnešenog materijala predemta obrade. Rezervoar je u osnovi vodom ispunjeni rezervoar koji neutrališe kinetičku energiju abrazivnih čestica.U praksi se primjenjuju tri osnovna oblika rezervoara:

a) vodeni bazen, b) potopljene čelične kugle i c) TiB2 ploče.

2.3. Catcher tank After abrasive waterjet passes through workpiece it still has substantial amount of kinetic energy which can cause damage of machining equipment. Also abrasive particles because of erosional interaction with workpiece lose a certain amount of energy. Mentioned loses of energy are insignificant in relation to overall kinetic energy with which the jet passes through material. Necessity for absorption of above mentioned kinetic energy results in application of catcher tank. The catcher is basically a tank filled with water that neutralizes kinetic energy of abrasive particles. In practice three types of catcher tanks are used:

a) tank filled with water b) submerged steel balls c) TiB2 plates. d)

Slika 4. Shematski prikaz tri osnovna oblika rezervoara [2] Figure 4. Schematic view of three basic types of catcher tanks [2]

3. ODRŽAVANJE KOMPONENTI ZA

REZANJE ABRAZIVNIM VODENIM MLAZOM

Proces održavanja komponenti obradnog sistema je neophodan ukoliko se želi postići visok stepen efikasnosti i preciznosti procesa obrade. Postupci i zahtjevi održavanja bitnih komponenti obradnog sistema će biti prikazan u tekstu koji slijedi. 3.1. Održavanje sistema za generisanje visokog pritiska- hidrauličnih pumpi Proces održavanja hidrauličnih pumpi sa radilicom je prvenstveno vezan za osiguranje pravilnog podmazivanja pokretnih komponenti hidraulične pumpe kao što su radilica, ležajevi radilice i pokretni klipovi. Pravilnim podmazivanjem se sprječava zagrijavanje navedenih komponenti i trošenje ležajeva do kojeg bi moglo doći neposrednim kontaktom između metalnih kuglica i tijela kuglastog ležaja.

3. MAINTENANCE OF COMPONENTS OF ABRASIVE WATERJET CUTTING The maintenance process of components for abrasive water jet cutting is necessary if we want to achieve a high efficiency and precision level of machining process. Procedures and maintenance requirements of important machining system components will be presented in following text. 3.1. Maintenance of system for high pressure production- hydraulic pumps Maintenance process of hydraulic pumps with crankshafts is basically connected with proper lubrication of hydraulic pump moving components such as crankshafts, bearings and moving pistons. Proper lubrication prevents heating of mentioned components and wasting of bearings, which would occur by direct contact between metal balls and ball bearing housing.


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Održavanje hidrauličnih pumpi sa radilicom je zasnovano na izmjeni ulja za podmazivanje unutar tačno definisanog vremenskog perioda koji se određuje u skladu sa intenzitetom rada hidraulične pumpe, a prema upustvu proizvođača.

Maintenance of hydraulic pumps with crankshafts is based on lubrication oil replacement in exactly defined period of time in accordance with hydraulic pump working intensity, and manufacturers instruction.

Slika 5. Osnovne komponente hidraulične pumpe sa radilicom [5]

Figure 5. Basic components of hydraulic pump with crankshaft [5]

Proces izmjene ulja počinje odvajanjem hidraulične pumpe od električnog motora i postavljanjem posude za sakupljanje ulja ispod cijevi za dovod ulja. Sljedeći postupak jeste odvajanje cijevi za dovod od zaptivača. Prilikom ovog postupka dolazi do isticanja ulja u prethodno postavljenu posudu ispod cijevi za dovod. Poslije isticanja ulja u posudu slijedi njeno odstranjivanje i postupak skidanja kartera skupa sa cijevi sa filterom i cijevi za dovod ulja. Kako bi se u potpunosti hidraulična pumpa očistila od korištenog ulja u praksi se primjenjuje komprimirani zrak koji se upušta u cijev sa filterom na kojoj se još uvijek nalazi čep. Nakon čišćenja se karter ponovo vraća na svoje mjesto uz vraćanje ostalih komponenti na mjesto i zamjenu zaptivača na kraju cijevi za dovod ulja. Novo ulje za podmazivanje se sipa kroz otvor cijevi sa filterom nakon čega je potrebno zamijeniti čep na navedenoj cijevi kao dokaz da je izvršena zamjena ulja.

Process of lubrication oil replacement starts with discharging of hydraulic pump from electric motor and placing drain pan under oil supply pipe. Next step is to disconnect oil supply pipe from the gasket. During this process lubrication oil flows below supply pipe into previously set drain pan . After oil flows into collecting jug, the collecting jug is removed and process of pump crankcase together with filter pipe and oil supply pipe. To completely clean the hydraulic pump from old used oli in practice compressed air is used, which is releared into the filter pipe with the cap still on it. After cleaning, crankcase is reattached on its place together with returnment of other components and replacement of the oil supply cap. New lubrication oil is filled trough opening of filter pipe, after that it is necessary to replace cap of this pipe as proof of lubrication oil replacement.


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3.2. Održavanje rezervoara za sakupljanje abraziva i odnešenog materijala tokom procesa rezanja Pošto je proces rezanja abrazivnim vodenim mlazom zasnovan na primjeni abrazivnih čestica i odnošenju materijala predmeta obrade koji se talože na dnu rezervoara u praksi se javlja neophodnost za održavanjem rezervoara koje ima za cilj postizanje visokog stepena efikasnosti i pouzdanosti procesa rezanja. Primarni cilj održavanja rezervoara jeste sprječavanje nagomilavanja nus produkata procesa rezanja koji mogu prouzrokovati pojavu korozije na dnu rezervoara. Nastala korozija na dnu rezervoara prouzrokuje trošenje istog što u konačnici može narušiti nepropusnost rezervoara. Kako bi se spriječila navedena pojava, proces održavanja rezervoara je zasnovan na nekoliko aktivnosti koje su navedene u tabeli 1.

3.2. Maintenance of catcher tank Because the abrasive waterjet cutting process is based on application of abrasive particles and workpiece material removal which is collected on tank bottom, in practice necessity for catcher tank maintenance occurs for high efficiency and reliability of machining process achievement. Primary target of catcher tank maintenance is to prevent cumulation of cutting process nus products that can produce corrosion on tank bottom. Created corrosion on tank bottom causes its wear that can infringe its permeability. To prevent this mentioned phenomenon maintenance process is based on several activities specified in table 1.

Tabela 1. Aktivnosti održavanja rezervoara za sakupljanje abraziva i odnešenog materijala tokom rezanja [5].

Aktivnosti održavanja Vremenski interval realizacije aktivnosti Sapiranje akumuliranih abrazivnih čestica sa rezne glave i radne površine

Na dnevnom nivou i u skladu sa potrebama za čistim radnim okruženjem

Očistiti nataloženi abrazivni materijal i nus proizvode procesa rezanja sa dna rezervoara

Kada se abrazivne čestice u kratkom vremenskom intervalu natalože na površini predmeta obrade

Kontrola unutrašnjih površina rezervoara i utvrđivanje potencijalnih oštećenja

Mjesečna kontrola i u slučaju kada su na metalnim letvicama vidljiva oštećenja

Čišćenje filtera za vodu Mjesečna kontrola

Pokretanje sistema za čišćenje vode nakon što se očišćeni rezervoar ispuni čistom vodom

Samo ukoliko sistem za rezanje abrazivnim vodenim mlazom koristi sistem za prečišćavanje vode

Dodavanje tvari za sprječavanje razvoja i širenja bakterija

Mjesečna kontrola i u slučaju da su pojava i razvoj bakterija vidljivi golim okom

Table 1. Catcher tank maintenance activities [5]. Maintenance activities Time interval for activities realisation Cleaning of accumulated abrasive particles of cutting head and working surface

Daily in accordance with need for clean working surface

Cleaning of accumulated abrasive particles and cutting process nus products from tank bottom

When abrasive particles accumulate on workpiece surface in short period of time

Control of tanks internal surfaces and determination of potential defects

Monthly control and when defects on metal slats are visible

Water filter cleaning Monthly Running of system for water cleaning after the tank is filled with clean water

Only if abrasive waterjet system uses system for water treatment

Addition of substances for prevention of corrosion

Monthly control in case when creation of bacteria is visible to eye.


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Slika 6. Istrošene metalne poprečne letvice i sistem za prečišćavanje vode [5] [6] [7] Figure 6. Worn metal slats and system for water cleaning [5] [6] [7].

Održavanje ostalih komponenti obradnog sistema za rezanje abrazivnim vodenim mlazom je prikazano kroz aktivnosti procesa održavanja naznačenih u tabeli 2.

Maintenance of other abrasive waterjet system components are specified in table 2.

Tabela 2. Održavanje radnih komponenti obradnog sistema Aktivnosti održavanja Vremenski interval realizacije aktivnosti

Odr

žava

nje

radn

ih

kom

pone

nti

Podmazivanje nosećih komponenti

Godišnje

Podmazivanje komponenti koje omogućavaju kretanje po X i Y osi Podmazivanje dijelova motora koji omogućava kretanje po Z osi Kontrola ventila i cijevi za dovođenje vodenog mlaza visokog pritiska

Demontaža mlaznice U skladu sa potrebama za postizanjem visoke tačnosti obrade

Table 2. Maintenance of machining system working components

Maintenance activities Time interval for activities realisation

Mai

nten

ance

of

wor

king

Lubrication of supporting components

Annual Lubrication of X nad Y movement motors Lubrication of Z movement motor Valve and pipe for waterjet guidanceb control

Nozzle removal In accordance with needs for achievement of high machining precision

3.3. Održavanje mlaznice i kontrola istrošenosti njenih komponenti Mlaznica predstavlja komponentu obradnog sistema koja ima direktan uticaj na preciznost procesa rezanja. Zbog visokih zahtjeva za preciznošću procesa rezanja i zahtjeva za postizanjem kompleksne geometrije rezova u praksi se javlja potreba za kontrolom istrošenosti komponenti mlaznice. Proces održavanja mlaznice je zasnovan na sljedećim aktivnostima: • zaustavljanje procesa rezanja i pripremne

aktivnosti za skidanje mlaznice, • skidanje mlaznice sa rezne glave,

3.3. Nozzle maintenance ang control of component wear Nozzle presents a component of machining system which has a direct impact on precision of cutting process. Due to high demands for cutting precision and demands for achievement of high complexity cuts geometry in practice demand for control of nozzle components wear occurs. Nozzle maintenance proces is based on following activities: • stopping of cutting process and preparation

activities for nozzle removal, • nozzle removal from cutting head,


193

• demontaža mlaznice, • čišćenje i kontrola istrošenosti komponenti

mlaznice, • izmjena istrošenih dijelova i montaža

mlaznice i • testiranje izmijenjenih komponenti.

Pošto proces demontaže i kontrole zahtijeva zaustavljanje cjelokupnog obradnog sistema i znatni utrošak vremena u praksi se definisanje potrebe za demontažom mlaznice vrši u skladu sa sljedećim pojavama: • isticanje vodenog mlaza iz komponenti

mlaznice, • nepravilno formiran vodeni mlaz, • umanjena preciznost i kvalitet rezanja, • pojava grešaka prilikom rezanja otvora ili

predmeta složene geometrije, • prekidnost reza, • usporen ili zaustavljen tok abrazivnih

čestica i • izlazak vode i abrazivnih čestica kroz

komoru za dodavanje abrazivnih čestica kao rezultat začepljenja mlaznice.

Komponente mlaznice koje se tokom procesa obrade troše i koje je potrebno kontrolisati kako bi se održala željena preciznost i kvalitet procesa rezanja su:

• safirna mlaznica, • disk komore za mješanje, • komora za mješanje i • fokusna cijev.

• nozzle removal • cleaning and control of wear nozzle

components • change of worn components and nozzle

installation and • testing of changed components.

Because process of changing nozzle components demands to stop the whole machining system which spents some time , in practice demand for nozzle components change is defined in accordance with following appearances: • water leaks in nozzle components, • incorrect forming of waterjet, • reduced precision and cut quality, • occurrence of defects while cutting

openings or objects with complex geometry,

• not achieved cut continuity, • slowed or stopped abrasive particles flow, • water and abrasive particles leaks trough

chamber for adding abrasive particles as result of nozzle clogging.

Nozzle components which wear off during machining process and which need to be controlled in order to obtain desired precision and cut quality are:

• jewel orifice, • mixing chamber discs, • mixing chamber and • focusing tube.

Slika 7. Osnovne komponente mlaznice koje je potrebno kontrolisati prilikom procesa održavanja [5]

Figure 7. Basic components of nozzle that need to be controlled during maintenance process [5].


194

Nakon procesa demontaže mlaznice njene komponente je potrebno očistiti kako bi se moguća oštećenja učinila vidljivim. Poslije intenzivnog čišćenja na komponentama navedenih na slici 7. je potrebno izvršiti kontrolu. Kretanjem abrazivnih čestica dolazi do trošenja unutrašnjih površina safirne dizne, komore za mješanje i povećanja prečnika otvora diska komore za mješanje i fokusne cijevi. Povećanjem prečnika otvora se smanjuje kinetička energija abrazivnih čestica i vodenog mlaza što kao rezultat ima nepravilno formiran abrazivni vodeni mlaz. Na slici 8. su prikazana oštećenja na komponentama mlaznice nastala usljed neposrednog kontakta između abrazivnih zrna i unutrašnjih površina komponenti mlaznice.

After nozzle removal its components need to be cleaned in order make potential defects visible. After intense cleaning of components shown on figure 7. it is necessary to control them. Movement of abrasive particles leads to wear of inner surfaces of jewel orifice, mixing chamber and increasement of mixing chamber discs and focusing tube opening diameter. With increasement of opening diameter kinetic energy of abrasive particles and waterjet is reduced, wich results with incorrect forming of abrasive waterjet. Defects of nozzle components formed due to direct contact between abrasive particles and inner surfaces of nozzle components are presented in figure 8.

Slika 8. Oštećenja nastala na safirnoj dizni, disku komore za mješane, komore za mješanje i fokusne cijevi [5].

Figure 8. Defects created on jewel orifice, mixing chamber disc, mixing chamber and focusing tube [5].

Oštećenja nastala na komponentama mlaznice predstavljaju indikatore za donošenje odluke o izmjeni navedenih komponenti ili o realizaciji procesa obrade bez izmjene istih. Ukoliko je konačna odluka nastavak procesa rezanja sa istim komponentama mlaznice tada je na osnovu intenziteta oštećenja potrebno odrediti rok aktivnosti održavanja u narednom periodu.

These created defects on nozzle components present indicators for decision making about change for mentioned components or machining process realisation without change of components. If the final decision is to continuation the cutting process with the same nozzle components, deadline of maintenance activities in the coming period should be set based on the intensity of demages.


195

4. ZAKLJUČAK Proces obrade abrazivnim vodenim mlazom predstavlja proces obrade čija efikasnost i preciznost zavise od stanja i kvaliteta unutrašnjih površina reznih komponenti prvenstveno mlaznice. Oštećenja navedenih komponenti rezultiraju neželjenim tokom abrazivnih čestica i vodenog mlaza koji u konačnici kao rezultat ima smanjen stepen efikasnosti procesa rezanja. U cilju smanjenja uticaja stanja reznih komponenti na efikasnost potrebno je pravovremeno održavati navedene komponente. Proces održavanja sistema za rezanje abrazivnim vodenim mlazom je složen proces kojeg čini više različitih aktivnosti. Karakteristike aktivnosti održavanja i vremenski interval njihovog realizovanja se definiše na osnovu karakteristika reznih komponenti i intenziteta korištenja istih. Pravovremenim održavanjem se omogućava postizanje visokog stepena efikasnosti, preciznosti i pouzdanosti navedenog sistema rezanja.

4. CONCLUSION Abrasive machining process presents a machining process which efficiency and precision depend on state and quality of inner surfaces of cutting components primarily nozzle. Defects of mentioned components result in undesired flow of abrasive particles and water jet that in the end results with low cutting process efficiency. In order tu reduce the impact of component state on efficiency it is necessary to timely maintain these components. Maintenance process of abrasive waterjet system is a very complex system which consists of many different activities. Characteristics of these activities and time interval for their realisation is defined in accordance with their characteristics and intensity of use. Prompt maintenance allows achievement of high efficiency, precision and reliability of mentioned cutting process.

5. LITERATURA - REFERENCES [1] https://www.omax.com/learn/how-does-

waterjet-work, [2] H.Lojo, Admir: „Obrada mlazom vode“,

Fakultet inžinjerskih nauka, Univerzitet Kragujevac.,

[3] http://www.omax.com/learn/how-does-waterjet-work,

[4] The OMAX JetMAchining Center Operator's Guide, OMAX Corporation 21409 72nd AvenueSout Kent USA 98032,

[5] http://www.waterjets.org/index.php?option=com_content&task=view&id=42&Itemid=33,

[6] OMAX 2652 JetMachining Center- katalog,

[7] Belić, Ilija: „Nekonvencionalni postupci obrade- obrada usmjerenom energijom“, Beograd, 2010

[8] Dragoje, Milikić: Nekonvencionalni postupci obrade (priručnik za studije i praksu) - Novi Sad, 2002.

[9] Jeleč, Ajdin: „Tehnologija obrade nekonvencionalnim postupcima obrade- Obrada abrazivnim vodenim mlazom“- Završni rad, Politehnički fakultet u Zenici, Univerzitet u Zenici, 2015

Coresponding author: Ajdin Jeleč ZEDA- Zenica Development Agency Email: [email protected] cell. : +387 62 148 019

*Rad je objavljen na IV Konferenciji „ODRŽAVANJE 2016, Zenica 02-04 juni 2016, pp. 27-34

* The paper was published in the IV Conference "MAINTENANCE 2016, Zenica 02-04 June 2016, pp. 27-34

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Table 1. Table titles (Style: Times New Roman, 11pt, Normal)

Engineering stress σe / MPa

Engineeringplastic strain εe,pl / %

True stress σt / MPa

True plastic strain εt,pl / %

250,0 0,00 250,8 0,00 250,0 0,21 250,8 0,21 285,7 1,35 290,0 1,34 322,7 2,13 330,1 2,10 358,4 3,06 370,0 3,00 393,1 4,35 411,0 4,24 423,6 6,05 450,1 5,85 449,7 8,76 490,1 8,36 457,0 15,79 530,1 14,59 467,9 21,58 570,0 19,45 475,0 29,77 617,5 25,94

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XX. REFERENCES (Style: Times New Roman, 11pt, Normal) [1] P.E. Nikravesh, Computer-Aided Analysis

of Mechanical Systems, Prantice Hall Inc.,Englewood Cliff,NJ,1988.

[2] Gordon Robertson, Graham Caldwell, Joseph Hamill, Gary Kamen, Saunders Whittlesey: Research Methods in Biomechanics, Human Kinetics; 2nd edition, 2014.

[3] Imai, M.: KAIZEN: the key to Japan’s competitive success, Editorial CECSA, Mexico. In Spanish, 1996.

[4] Nemoto, M.: Total quality control for management. Strategies and techniques from Toyota and Toyoda Gosei, Prentice-Hall, Englewood Cliffs, NJ, 1987.

[5] Cheser, R.: The effect of Japanese KAIZEN on employee motivation in US manufacturing, Int J Org Anal 6(3):197–217, 1998.

[6] Aoki, K.: Transferring Japanese KAIZEN activities to overseas plants in China, Int J Oper Prod Manag 28(6):518–539, 2008.

[7] Tanner, C.; Roncarti, J.: KAIZEN leads to breakthroughs in responsiveness and the Shingo prize at Critikon, Natl Prod Rev 13(4):517–531, 1994.

[8] Rink, J.: Lean can save American manufacturing. Reliable plant. http://www.reliableplant.com/Read/330/lean-manufacturing-save. Accessed at 14 April 2014.

[9] SolidWorks, http://www.solidworks.com (12.5.2015)

Coresponding author: Name and surname Institution Email: [email protected] Phone: +xxx xx xxxxxx (Style: Times New Roman, 11pt, Bold)

Agencija ZEDA je razvojna institucija čiji je zadatak da kreira razvojne prioritete Grada Zenice i da stvara i koordinira partnerstva za njihovu realizaciju.Laboratorija LIND je formirana kao odjeljenje u Agenciji ZEDA, a nastala je kao rezultat projekta MENTOR finansiranog sredstvima Evropske unije iz fondova za razvoj BIH. Partneri i sufinansijeri u real-izaciji projekta bili su Grad Zenica, Regionalna razvo-jna agencija REZ, Vlada ZE-DO kantona i Federalno ministarstvo razvoja, poduzetništva i obrta. Ispitivanje sigurnosti proizvoda obuhvata:• Ispitivanje namještaja (ispitivanja se izvode u pros-

torijama LIND-a)• Ispitivanje dječijih igrališta (ispitivanja se izvode

na terenu)Oblast ispitivanja sigurnosti proizvoda se prvenstveno odnosi na mehanička ispitivanja namještaja i opreme za dječija igrališta gdje se primjenom različitih statičkih, dinamičkih i mjernih metoda definiše usklađenost proizvoda sa zahtjevima standarda, a samim tim sig-urnost proizvoda za upotrebu.

VALIDNOST ISPITIVANJA

Institut za akreditiranje BIH – BATA je u martu 2016. go-dine laboratoriji LIND izdao CERTIFIKAT O AKRED-ITACIJI kojim je potvrđeno da laboratorija ispunjava zahtjeve standarda BAS EN ISO/IEC 17025:2006 u pogledu osposobljenosti za izvođenje mehaničkih ispi-tivanja namještaja i opreme za dječija igrališta. Sva ispi-tivanja realizovana od strane laboratorije LIND imaju validnost u svim evropskim zemljama i drugima zemlja-ma koje pokriva evropska akreditacija (EA).

Kontinuirano povećanje broja ispitivanja u laboratoriji LIND, dokaz je da su MSP prepoznali laboratoriju kao partnera na putu ka poboljšanju kvaliteta svojih proiz-voda u skladu s važećim BAS EN i EU standardima za navedene oblasti. Na ovaj način domaći proizvođači namještaja ne moraju svoje proizvode slati na ispi-tivanja u druge zemlje te na taj način štede vrijeme i novac.

MAŠINE I OPREMA ZA ISPITIVANJE

Ispunjavanjem preduslova za izvođenje ispitivanja u skladu sa zahtjevima standarda, obučeno, stručno os-oblje LIND-a pristupa ispitivanju predmeta ispitivanja na nekoliko ispitnih mašina, nabavljenih od proiz-vođača “Hegewald&Peschke GmbH“ i namijenjene su za izvođenje mehaničkih ispitivanja namještaja. Kako bi se osiguralo postizanje visoke tačnosti i pouzdanosti rezultata ispitivanja, ispitne mašine su kalibrisane od strane renomiranih akreditiranih kuća. Za ispitivanje namještaja koriste se sljedeće mašine/uređaji:1. 3D mjerni uređaj2. Uređaj za dugotrajno ispitivanje ladica i vrata3. Uređaj za ispitivanje stabilnosti stolica s pripada-

jućom opremom4. Uređaj za ispitivanje na udar klatnom 5. Univerzalni ispitni uređaj za namještaj s upravl-

jačkom jedinicom 6. Uređaj za ispitivanje predmeta na udar7. Ostala oprema i uređaji za ispitivanje namještaja

PODRUČJE ISPITIVANJA LIND-a

LIND Laboratorija za ispitivanje sigurnosti proizvoda realizuje ispitivanja u akreditiranom i neakreditiranom području. U akreditiranom području vršimo ispitivanja sigurnosti namještaja i opreme za dječija igrališta.

ISPITIVANJE DJEČIJIH IGRALIŠTA

Ispitivanje dječijih igrališta podrazumijeva ispitivanje opreme za dječija igrališta i igrališne površine. Os-posobljeno stručno osoblje LIND-a izvršilo je znatan broj ispitivanja dječijih igrališta. Metodama ispitivanja definisanih BAS EN standardima se nastoji umanjiti stepen rizika od različitih oblika povreda djece ili ih svesti na prihvatljivi minimum te na taj način obezbi-jediti sigurnost opreme za dječija igrališta. Za izvođen-je ispitivanja opreme za dječija igrališta i igrališne pov-ršine, koriste se kalibrisani mjerni uređaji i oprema.

LIND - LABORATORIJA ZA ISPITIVANJE SIGURNOSTI PROIZVODAZENIČKA RAZVOJNA AGENCIJA ZEDA D.O.O.

TEKUĆE AKTIVNOSTI I BUDUĆI PLANOVI

U toku je realizacija projekta MENTOR II čiji je glavni implementator Agencija ZEDA, glavni finansijer EU, su-finansijer Federalno ministarstvo razvoja, poduzetništva i obrta. Implementatori projekta, kao partneri u projektu su Grad Zenica i Univerzitet u Zenici. Projektom se želi stimulisati ekonomski razvoj unaprjeđenjem konkurent-nosti MSP, na način da se uvođenjem sistemskog ispiti-vanja i razvoja finalnih proizvoda građevinske stolarije, njihovi proizvode usklade sa bh i EU standardima u po-gledu mehaničkih karakteristika i energetske efikasnosti. Krajem septembra 2016. godine očekuje se montiranje

ispitnih mašina u prostorijama LIND-a. U narednim mjesecima implementacije projekta, pred-viđene su i aktivnosti na odabiru laboratorije za ospos-obljavanje i edukaciju laboratorijskog osoblja LIND-a za izvođenje praktičnih ispitivanja građevinske stolari-je i fasadnih elemenata. Ispitivanje proizvoda građevin-ske stolarije je planirano od kraja 2016. godine.Planom laboratorije LIND predviđeno je i uvođenje novih BAS/EN standarda za ispitivanje nogometnih golova, rukometnih golova, opreme za košarku, opreme za odbojku, opreme za više sportova i igrališnih pov-ršina, čime će laboratorija LIND proširiti akreditirano područje ispitivanja.

Tabela 1. Ispitivanje namještaja

R.b. Predmet ispitivanja materijali/proizvodi Vrste ispitivanja/Mjerna karakteristika

Metode iliSpecifikacije

1. Namještaj – Namještaj za sjedenje Metode ispitivanja za određivanje čvrstoće i trajnosti BAS EN 1728:2014+ Cor 1:2014

2. Namještaj – Stolovi Metode ispitivanja za određivanje čvrstoće, trajnosti i stabil-nosti BAS EN 1730:2013

3. Stolice i stolovi za odgojno-obrazovne usta-nove

Dio 1: Funkcionalne dimenzije BAS EN 1729-1:20094. Dio 2: Sigurnosni zahtjevi i metode ispitivanja BAS EN 1729-2:2013

5. Kućni i kuhinjski elementi za odlaganje i radne ploče Sigurnosni zahtjevi i metode ispitivanja BAS EN 14749:2010

6. Uredski namještaj – Uredske radne stolice Dio 1: Dimenzije - Određivanje dimenzija + Amandman AC BAS EN 1335-1:2002+Cor 1:2005

7.Kancelarijski namještaj – Kancelarijska radna stolica

Dio 2: Sigurnosni zahtjevi BAS EN 1335-2:2010Izuzev: 4.4

8. Dio 3: Metode ispitivanjaBAS EN 1335-3:2010+Cor 1:2011Izuzev: 7.2.5,7.3.3,7.3.5 i 7.4

9.Kancelarijski namještaj – Radni stolovi I pultovi

Dio 1: Dimenzije BAS EN 527-1:2012

10. Dio 2: Mehanički sigurnosni zahtjevi BAS EN 527-2:2005

11. Dio 3: Metode ispitivanja za određivanje stabilnosti i me-haničke čvrstoće konstrukcije BAS EN 527-3:2009

12. Namještaj - Čvrstoća, trajnost I sigurnost Zahtjevi za namještaj za sjedenje za kućnu upotrebu BAS EN 12520:201113. Kućni namještaj – Sjedala Određivanje stabilnosti BAS EN 1022:200914. Namještaj – Čvrstoća, trajnost i sigurnost Zahtjevi za stolove u domaćinstvu BAS EN 12521:201015. Namještaj – Dječiji krevetići i sklopivi dječiji

krevetići za kućnu upotrebu Dio 1: Sigurnosni zahtjevi BAS EN 716-1+A1:2014

16. Dio 2: Metode ispitivanja BAS EN 716-2+A1:201417.

Vanjski namještaj – Sjedala i stolovi za kam-povanje, za kućnu i javnu upotrebu

Dio 1: Opći sigurnosni zahtjevi BAS EN 581-1:2009

18. Dio 2: Mehanički sigurnosni zahtjevi i metode ispitivanja za namještaj za sjedenje BAS EN 581-2:2010

19. Dio 3: Mehanički sigurnosni zahtjevi i metode ispitivanja za stolove BAS EN 581-3:2009

20. Namještaj za sjedenje koji nije za kućnu upotrebu

Namještaj-čvrstoća,trajnost i sigurnost - Zahtjevi za namještaj za sjedenje koji nije za kućnu upotrebu

BAS EN 16139:2014BAS EN 16139/ Cor1:2014

Tabela 2. Ispitivanje opreme za dječija igrališta i određivanje površine potrebne za opremu

R.b. Predmet ispitivanja materijali/proizvodi

Vrste ispitivanja/Mjerna karakteristika

Metode iliSpecifikacije

1.

Oprema za dječija igrališta i određivanje površine po-trebne za opremu

Dio 1: Opći sigurnosni zahtjevi i ispitne metode *BAS EN 1176-1:20112. Dio 2: Dodatni posebni sigurnosni zahtjevi i ispitne metode za ljuljačke *BAS EN 1176-2:20113. Dio 3: Dodatni posebni sigurnosni zahtjevi i ispitne metode za tobogane *BAS EN 1176-3:20114. Dio 4: Dodatni posebni sigurnosni zahtjevi i ispitne metode za žičare *BAS EN 1176-4:20115. Dio 5: Dodatni posebni sigurnosni zahtjevi i ispitne metode za vrteške *BAS EN 1176-5:2011

6. Dio 6: Dodatni posebni sigurnosni zahtjevi i ispitne metode za sprave za njihan-je *BAS EN 1176-6:2011

7. Dio 10: Dodatni posebni sigurnosni zahtjevi i ispitne metode za potpuno ograđenu opremu za igru *BAS EN 1176-10:2011

8. Dio 11: Dodatni posebni sigurnosni zahtjevi i ispitne metode za mreže za pen-janje *BAS EN 1176-11:2011

* Metode se izvode na terenu

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