NONDESTRUCTIVE AND DESTRUCTIVE EVALUATION OF … and destructive... · musnah dan modulus...

NONDESTRUCTIVE AND DESTRUCTIVE EVALUATION OF WOOD STRENGTH AND ITS RELATION TO CELLULAR MICROSTRUCTURE

Nurul Faziha binti Ibrahim

Master of Science 2010

J "' 1 laJUUmal Axuuc OJ ilVERSITI MALAYSIA SARA\V,

P.KHIDMAT MAKLUMAT AKADEMIK

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NONDESTRUCTIVE AND DESTRUCTIVE EVALUATION OF WOOD STRENGTH AND IT'S RELATION TO CELLULAR MICROSTRUCTURE

NURUL F AZIHA BINTI IBRAHIM

A thesis submitted In fulfillment of requirements for the degree of Master Science

Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARAW AK

2010

DECLARATION

No portion of the work referred to in this dissertation has been submitted in support of an application for another degree of qualification of this or any other university or institution of higher learning.

;=ei i

Nurul Faziha Binti Ibrahim

Faculty of Resource Science and Technology

Universiti Malaysia Sarawak

ACKNOWLEGMENT

First and foremost, I would like to thank the Faculty of Resource Science and

Technology, Faculty of Engineering and the Centre of Graduate Studies, UNIMAS for

providing me the opportunity, scholarship and facilities to conduct this research.

I also would like to extend my gratitude and appreciation to my supervisor, Associate

Professor Dr. Ismail Jusoh and Associate Professor Dr. Sinin Hamdan for their invaluable

advice, constant support, guidance and patience throughout the process of this research.

I am also grateful to my fellow coursemates, Nur Afnie Farysha Binti Hamsah,

Sharifah Mona Abdul Aziz, Farawahida Abu Zahrin, Rezaur Rahman and Saiful Islam;

laboratory technicians, Mr. Salim, Mr. Rizan, Mr. Sabariman for their technical guidance,

kindness, friendship and company. I also would like to thank Timber Research and Technical

Training Centre (TRTTC) for their assistance in preparing my wood samples.

My sincere thanks and love go to my parents, Ibrahim Bin Jusoh and Naemah Binti

Mat Zin; brother, Mohd Fahizan, sisters, Filzana, Ida Firdaus, Fadzilah and Fatin Nadia for

their encouragement and moral support.

11

ABSTRACT

(Non-destructive evaluation (NDE) of wood is a method of identifying wood quality without

damaging the samples and its eliminate the tedious specimen preparation in order to determine

the mechanical properties of wood. Wood properties can be determined rapidly by in situ

inspection during its service life or measured directly from standing trees without reducing the

economic value of its timber. This study assess the feasibility of free-free flexural vibration

method, one of NDE techniques for estimating the wood stiffness of plantation species

namely Acacia mangium, Hevea brasiliensis and Paraserianthes mOluccanaJ The specific

objective of this study were (i) determine the dynamic modulus of elasticity (DMOE) on the

three plantation species, (ii) establish the relationship between DMOE obtained from non

destructive and modulus of elasticity (MOE), modulus of rupture (MOR), Young's modulus

(E) and maximum crushing strength (MCS) obtained from destructive test, (iii) evaluate the

effects of tension wood on DMOE, MOE and MaR, and (iv) analyze the relationship between

anatomical properties and mechanical properties. For this purpose, wood specimens with

dimension 20 mm (T) x 10 mm (R) x 340 mm (L) were prepared for non-destructive test

according to tension wood and opposite wood to determine DMOE. The results from the non

destructive test were compared with destructive tests namely three-point bending and

compression parallel to grain where the samples were .prepared according to the British

Standard. The DMOE was also compared with MOE and MOR obtained from three-point

bending test using the non-destructive test's samples. Results showed that tension wood

recorded greater DMOE mean values than opposite wood. A. mangium recorded higher

DMOE in both tension and opposite wood followed by H brasiliensis and P. moluccana.

Destructive tests also showed that A. mangium recorded the highest mean MOE and MaR

III

values followed by H brasiliensis and P. moluccana as determined by three-point bending

test. Regression analyses showed that strong relationship were observed between DMOE and

MOE detennined from non-destructive samples (ND samples) in both of tension (r= 0.92)

and opposite wood (r2=0.79). However, DMOE and MOE obtained from British Standard

samples (BS samples) were not correlated. In order for DMOE to be meaningful and able to

predict MOE, correction factor has to be introduced to DMOE. Following inclusion of

correction factor (CF), DMOE' was significantly correlated with MOE in A. mangium

(R=0.80 and 0.88) and H brasiliensis (R=0.85 and 0.90) in tension and opposite wood,

respectively. However, it did not successfully determined DMOE' in P. moluccana due to its

low density that yielded large CF values. Between DMOE and MOR, only tension wood

recorded good relationship (r2=0.70) compared to opposite wood (r2=0.46) in all species

combined from ND samples. Anatomically, tension wood is characterized by thicker fibre

wall, longer fibre, larger fibre diameter, smaller vessel diameter and small microfibril angle

(MFA). The relationship between anatomical properties and mechanical properties showed

that fibre wall thickness gave significant effect on DMOE in all individual species in both of

tension and opposite wood. The fibre wall thickness significantly effect the MOE and MOR in

all individual species in tension wood but only A. mangium and P. moluccana in opposite

wood. For all species combined, fibre length was significantly correlated with DMOE, MOE

and MOR in tension wood but only correlated to MOR in opp<?site wood. Ray height was

significantly correlated with DMOE and MOE in opposite wood of the species studied. Fibre

lumen diameter and fibre diameter were significantly correlated with MOE and MOR only in

opposite wood. From the results, it can be concluded that the free-free flexural vibration

method has the potential to predict the mechanical properties of the plantation species.

IV

UJIAN TANPA MUSNAH DAN MUSNAH KEKUATAN KAYU DAN

HUBUNGANNYA DENGAN STRUKTUR MIKRO SEL

ABSTRAK

Ujian tanpa musnah (NDE) ialah satu kaedah untuk mengenal pasti kualiti kayu tanpa

merosakkan sampel dan menghapuskan penyediaan sampel yang remeh. Sifat-sifat kayu dapat

ditentukan berulang kali dengan menguji secara 'in situ' semasa servis atau secara terus dari

pokok tanpa menyusut nilai ekonomi kayu tersebut. Kajian ini melihat keupayaall kaedah

getaran melintang secara bebas untuk mengukur kekuatan spesies ladang hutan iaitu Acacia

mangium. Hevea brasiliensis dan Paraserianthes moluccana. Objektif spesijik kajian ini

adalah untuk (i) menentukan modulus kekenyalan dinamik (DMOE) ke atas tiga spesies

ladang hutan, (ii) menentukan hubungan antara DMOE diperolehi daripada ujian tanpa

musnah dan modulus kekenyalan (MOE), modulus patahan (MOR), modulus Young (E) dan

kekuatan musnah maksimum (MCS) diperolehi daripada ujian musnah, (iii) menguji kesan

kayu tegangan terhadap DMOE, MOE, MOR, E dan MCS dan (iv) menguji hubungan di

antara sifat-sifat anatomi dan sifat-sifat mekanikal. Bagi tujuan ini, spesimen kayu bersaiz 20

mm (T) x 10 mm (R) x 340 mm (L) telah disediakan untuk ujian tanpa musnah mengikut kayu

tegangan dan kayu normal untuk menentukan DMOE. Keputusan dari ujian tanpa musnah

ujian musnah iaitu lenturan tiga litik dan mampatan selari iradibandingkan dengan

mengguna piawai British. DMOE juga dibandingkan dengan MOE dan MOR diperolehi dan

lenturan tiga titik menggunakan sampel ujian tanpa musnah. Keputusan ini menunjukkan

kayu tegangan mencatatkan nilai DMOE yang tinggi berbanding dengan kayu norma/. A.

mangium mencatatkan DMOE yang tinggi dalam kayu tegangan dan kayu normal diikuti oleh

v

H brasiliensis dan P. moluccana. Ujian musnah juga menunjukkan A. mangium mencatatkan

purata nilai MOE dan MOR tertinggi diikuti oleh H brasiliensis dan P. moluccana yang

ditentulcan dari ujian lenturan tiga titik. Keputusan analisis menunjukkan hubungan yang kuat

antara DMOE dan MOE yang ditentukan dari sampel tanpa musnah (sampel ND) dalam kayu

tegangan (r2= 0.92) dan kayu normal (r2=0. 79). Walau bagaimanapun, tiada korelasi antara

DMOE dan MOE diperolehi dari sampel mengikut piawaian British (sampel BS). Untuk

menjadilcan DMOE lebih bermakna dan dapat meramalkan MOE, laktor pembetulan telah

diperkenallcan terhadap DMOE. Sebaik sahaja kemasukan laktor pembetulan (CF), DMOE'

didapati berkorelasi secara signifikan terhadap MOE dalam A. mangium (R=0.80 dan 0.88)

dan H brasiliensis (R=0.85 dan 0.90) masing-masing dalam kayu tegangan dan kayu normal.

Walau bagaimanapun, DMOE' tidak sesuai diaplikasikan dalam P. moluccana kerana

ketumpatannya yang am at rendah menyebabkan julat CF yang terlalu besar. Antara DMOE

dan MOR, hanya kayu tegangan mencatatkan hubungan yang baik (/=0.70) berbanding kayu

normal (/=0.46) dalam kombinasi semua spesies dari sampel ND. Berdasarkan anatomi,

kayu tegangan bercirikan dinding gentian yang tebal, gentian yang panjang, diameter gentian

yang besar, diameter liang yang kecil, dan sudut mikrojibril (MFA) yang kecil. Hubungan

antara sifat anatomi dan mekanikal menunjukkan ketebalan dinding gentian menunjukkan

kesan yang signifikan terhadap DMOE dalam semua spesies sama ada dalam kayu tegangan

dan kayu normal. Ketebalan dinding gentian juga memberi kesan signifikan terhadap MOE

dan MOR dalam semua spesies individu dalam kayu tegangan tetapi hanya A. mangium dan

P. moluccana dalam kayu normal. Kombinasi data bagi semua spesies menunjukkan panjang

gentian berkorelasi secara signifikan terhadap DMOE, MOE dan MOR dalam kayu tegangan

lelapi hanya berkorelasi terhadap MOR dalam kayu normal. Panjang ruji berkorelasi secara

signifilcan terhadap DMOE dan MOE dalam kayu normal. Diameter lumen gentian dan

VI

diameter gentian berkorelasi terhadap MOE dan MaR. Kesimpulan dari kajian ini

menunjukkan bahawa kaedah getaran melintang bebas berpotensi meramalkan sifat

mekanikal spesies ladang hutan.

VB

Pu at Khidm~ lJu..nlllt Akad mi... UNIVERSITI MALA S SAI{AW K

TABLE OF CONTENTS

Page

DECLARATION

ACKNOWLEDGMENT 11

ABSTRACT

TABLE OF CONTENTS Vlll

III

ABSTRAK v

xiiLIST OF FIGURE

LIST OF TABLE xv

LIST OF SYMBOLS XIX

LIST OF APPENDICES xx

CHAPTER ONE: INTRODUCTION

1.1 Background 1

41.2 Objectives

CHAPTER TWO: LITERATURE REVIEW

2.1 Acacia mangium Willd. 7

2.2 Hevea brasiliensis Muell. Arg. 11

2.3 Paraserianthes moluccana (L.) Nielsen 14

2.4 Properties of tension wood 17

2.5 Non-destructive evaluation techniques 20

2.6 Principle of free-free flexural vibration 30

2.7 Dynamic Modulus of Elasticity (DMOE) 30

Vlll

332.8 Relationship between anatomy and wood properties

CHAPTER THREE: MATERIALS AND METHODS

373.1 Sample collection

403.2 Non-destructive testing

3.2.1 Experimental apparatus 40

3.2.2 Determination of DMOE using free-free flexural vibration 45

3.3 Destructive testing 46

3.3.1 Static bending test 46

3.3.2 Compression parallel to grain 48

3.4 Quantification of anatomical properties 50

3.4.1 Wood material 50

3.4.2 Cube softening 50

3.4.3 Cube sectioning 51

3.4.4 Staining 51

3.4.5 Permanent mounting 51

3.4.6 Determination of fibre length 52

3.4.7 Determination of microfibril angle (MFA) 53

3.4.8 Measurement of anatomical parameter 54

3.5 Determination of air-dry density and specific gravity 57

573.6 Data analyses

CHAPTER FOUR: RESULTS

594.1 Vibrational properties of plantation species

IX

Dynamic Modulus of Elasticity (DMOE) 60

Modulus of Elasticity (MOE), Modulus of Rupture (MOR), 61

Young's Modulus (E) and Maximum Crushing Strength (MCS)

Anatomical properties of Acacia mangium, Hevea brasiliensis 64

and Paraseriathes moluccana

4.5 Air-dry density and specific gravity ofAcacia mangium, Hevea brasiliensis 67

and Paraseriathes moluccana

4.6 Relationship between MOE and MOR, and E and MCS 69

4.7 Variation of MOE and MOR values determined from 77

ND samples and BS samples

4.8 Relationship between DMOE and frequency 79

4.9 Relationship between DMOE and MOE and MOR 81

modulus of elasticity (MOE), and modulus of rupture (MOR)

4.10 Relationship between DMOE' and MOE following application of 88

correction factor

4.l1 Effect of anatomical properties on DMOE, MOE and MOR 92

4.11.1 Effect of anatomical properties on DMOE 92

4.11.2 Effect of anatomical properties on MOE 97

4.1l.3 Effect of anatomical properties on MOR 100

4.l2 Relationship DMOE and air-dry density 104

CHAPTER FIVE: DISCUSSION

5.l Dynamic Modulus of Elasticity (DMOE), Modulus of Elasticity (MOE), 107

Modulus of Rupture (MOR), Young's Modulus (E) and

x

Maximum Crushing Strength (MCS) of plantation species

5.2 Relationship among DMOE and MOE, and MOR 110

5.3 The effect of tension wood on non-destructive and destructive properties 113

of plantation species

1165.4 The effect of anatomical properties on DMOE, MOE and MOR

CHAPTER SIX: SUMMARY AND CONCLUSION

6.1 Summary 120

1226.2 Conclusion

125REFERENCES

xi

Figure

LIST OF FIGURE

Descriptions Page

Figure 3.1 Sampling for bolt 1, bolt 2 and bolt 3 38

Figure 3.2 (a) Sampling for tension and opposite wood for each bolt 39

(b) The cross section of tension and opposite wood

Figure 3.3 Sample preparation scheme from the log 39

Figure 3.4 Schematic diagram offree~free flexural vibration method 40

Figure 3.5 Free-free flexural vibration testing system 41

Figure 3.6 An example of natural frequency of wood specimen obtained from 43

free-free flexural testing system using Ix resolution

Figure 3.7 An example of natural frequency of wood specimen obtained from 43

free-free flexural testing system using 20x resolution

Figure 3.8 The ratio of nodal point from free ends to length of sample (xiI) 44

for mode 1

Figure 3.9 Three-point bending test 47

Figure 3.10 Scheme for determination of specific gravity, anatomical properties 48

and fibre length from bending specimen failure

Figure 3.11 Compression parallel to grain 49

Figure 3.12 Position of sections 52

Figure 3.13 Photomicrograph of fibre under confocal laser scanning microscope 53

Figure 3.14 Photomicrograph of microfibril angle (MFA) under compound 54

Microscope, 40x

Figure 3.15 Photomicrograph of (a) fibre cell with G-Iayer in H brasiliensis, 56

xii

Figure 4.1

Figure 4.2

Figure 4.3

Figure 4.4

Figure 4.5

Figure 4.6

Figure 4.7

(b) fibre cell in P. moluccana, (c) vessel in H brasiliensis and

(d) ray cells in A. mangium

Relationship between MOE and MOR in ND samples 70

(20 mm (T) x 10 mm (R) x 340 mm (L)) for A. mangium,

H brasiliensis and P. moluccana in (a) tension wood and

(b) opposite wood

The relationship between MOE and MOR in BS samples 71

(20 mm (T) x 20 mm (R) x 300 mm (L)) for A. mangium,


(b) opposite wood

The relationship between MOE and MOR in ND samples 72

(20 mm (T) x 10 mm (R) x 340 mm (L)) for all species combined m

(a) tension wood and (b) opposite wood

The relationship between MOE and MOR in BS samples 73

(20 mm (T) x 20 mm (R) x 300 mm (L)) for all species combined in


The relationship between E and MCS in A. mangium, 75

H brasiliensis and P.moluccana in (a) tension wood and

(b) opposite wood

The relationship between E and MCS for all species combined in 76


The relationship between DMOE and frequency in A. mangium, 80


(b) opposite wood

Xlll

Figure 4.8 The relationship between DMOE and MOE in A. mangium, 82

H brasiliensis and P. moluccana for ND samples

(20 mm (T) x 10 mm (R) x 340 mm (L)) in (a) tension wood and

(b) opposite wood

Figure 4.9 The relationship between DMOE and MOE for all species combined 83

in ND samples (20 mm (T) x 10 mm (R) x 340 mm (L)) in


Figure 4.10 The relationship between DMOE and MOR in A. mangium, 86

H brasiliensis and P. moluccana for ND samples

(20 mm (T) x 10 mm (R) x 340 mm (L)) in (a) tension wood and

(b) opposite wood

Figure 4.11 The relationship between DMOE and MOR for all species combined in 87

ND samples (20 mm (T) x 10 mm (R) x 340 mm (L)) in (a) tension wood

and (b) opposite wood

Figure 4.12 The relationship between MOE and DMOE' in (a) tension wood and 91

(b) opposite wood from BS samples

Figure 4.13 The relationship between DMOE and density in A. mangium, 105

H. brasiliensis and P. moluccana in (a) tension wood and

(b) opposite wood

Figure 4.14 The relationship between DMOE and density in all species combined 106

in (a) tension wood and (b) opposite wood

xiv

LIST OF TABLE

Table Descriptions Page

Table 2.1 Mean MOE, MOR, E and MCS values ofA. mangium 9

Table 2.2 Average values of fibre length, fibre diameter, fibre lumen diameter, 10

fibre wall thickness, vessel diameter, ray height and ray diameter of

A. mangium

Table 2.3 Mean MOE, MOR, E and MCS values of H brasiliensis 12

Table 2.4 Average values of fibre length, fibre diameter, 14

fibre wall thickness, vessel diameter, ray height, vessel frequency

and ray frequency of H brasiliensis

Table 2.5 Mean MOE and MOR values of P. moluccana 16

Table 2.6 Average values of fibre length, vessel diameter and vessel 16

frequency of P. moluccana

Table 2.7 The wood study using differences of non-destructive techniques 26

Table 3.1 Tree characteristics of A. mangium, H brasiliensis and P. moluccana 38

Table 4.1 Mean values of natural frequency in tension and opposite wood of 60

A. mangium, H brasiliensis and P. moluccana

Table 4.2 Mean values of DMOE in tension and opposite wood of 61


Table 4.3 Mean values of MOE and MOR in tension and opposite wood obtained 62

according to British Standard (B.S.373: 1957)

Table 4.4 Mean values of MOE and MOR in tension and opposite wood obtained 63

xv

For ND samples determined destructively using British Standard

Table 4.5 Mean values of E and MCS in tension and opposite wood of 64


Table 4.6 Comparison of anatomical properties in tension wood and 65

opposite wood of A. mangium


opposite wood of H brasiliensis


opposite wood of P. moluccana

Table 4.9 Mean air-dry density and specific gravity in A. mangium, 68

H brasiliensis and P. moluccana of tension and opposite wood

Table 4.10 Comparison between mean air-dry density determined in 68

tension wood and opposite wood of A. mangium, H brasiliensis

and P. moluccana

Table 4.11 Differences between ND samples and BS samples in terms of MOE 78

and MOR in A. mangium, H brasiliensis and P. moluccana

in tension and opposite wood

Table 4.12 Differences between BS samples and ND samples in terms of MOE 78

and MOR for all species combined in tension and opposite wood

Table 4.13 Comparison between mean values ofDMOE and MOE in ND samples 84

Table 4.14 Pearson correlation (R) between DMOE and MOE, and DMOE and 88

MOR in tension and opposite wood in BS sample,

20mm (T) x 20mm (R) x 300mm (L)

xvi

Table 4.15 Pearson correlation between MOE and DMOE after the correction 90

factor was included in BS sample, 20mm (T) x 20mm (R) x 300mm (L)

Table 4.16 Multiple linear regression of anatomical properties on dynamic 93

modulus of elasticity (DMOE) in tension and opposite wood

of A. mangium



of H brasiliensis



of P. moluccana


modulus of elasticity (DMOE) for all species combined in tension

and opposite wood

Table 4.20 Multiple linear regression of anatomical properties on modulus of 97

elasticity (MOE) in tension and opposite wood of A. mangium


elasticity (MOE) in tension and opposite wood of H brasiliensis


elasticity (MOE) in tension and opposite wood of P.moluccana


elasticity (MOE) for all species combined in tension and opposite wood


rupture (MOR) in tension and opposite wood of A. mangium

XVll

4.25 Multiple linear regression of anatomical properties on modulus of 101

rupture (MOR) in tension and opposite wood of H brasiliensis

4.26 Multiple linear regression of anatomical properties on modulus of 102

rupture (MOR) in tension and opposite wood of P. moluccana

Multiple linear regression of anatomical properties on modulus of 103

rupture (MOR) for all species combined in tension and opposite wood

xviii

LIST OF SYMBOLS

= dynamic modulus of elasticity

= dynamic modulus of elasticity following inclusion of

correction factor

= modulus of elasticity

= modulus of rupture

= Young's modulus

= maximum crushing strength

=period of strain oscillation

= lateral deflection of beam

= distance along the beam

= speed of sound in the beam

= radius of gyration

= moment of inertia

= cross section of beam

= density of beam

= constant in Euller-Bernoulli elementary theory

= beam depth

= beam width

= beam length

= natural frequency of specimen

= mode of vibration

XlX

LIST OF APPENDICES

Figure AI: Photomicrograph of Acacia mangium tension wood sections, (a) transverse

section, 200x, (b) tangential section, 200x, (c) fibre cell, 600x and (d) radial

section, 200x using confocal laser scanning microscope

Figure A2: Photomicrograph of Acacia mangium opposite wood sections, (a) transverse



Figure A3: Photomicrograph of Hevea brasiliensis tension wood sections, (a) transverse



Figure A4: Photomicrograph of Hevea brasiliensis opposite wood sections, (a) transverse



Figure A5: Photomicrograph of Paraserianthes moluccana tension wood sections, (a)

transverse section, 200x, (b) tangential section, 200x, (c) fibre cell, 600x and (d)

radial section, 200x using confocal laser scanning microscope

xx

figure A6: Photomicrograph of Paraserianthes moluccana opposite wood sections, (a)

transverse section, 200x, (b) tangential section, 200x, (c) fibre cell, 600x and (d)

radial section, 200x using confocal laser scanning microscope

XXI

CHAPTER ONE

INTRODUCTION

Background

In Malaysia, forest plantation began in 1957 with the planting of teak (Tectona

grandis) in northern state of Perlis and Kedah (Nik Muhamad and Paudyal, 1999). Then, the

plantation of tropical pine especially Pinus caribaea var. hondurensis took place which was

meant for pulp and paper industry. However, due to difficulty in obtaining good quality seeds

of P. caribaea, the plantation has been shifted to short-rotation (IS-years rotation) tropical

species such as Acacia mangium, Tectona grandis, Gmelina arborea and Falcataria

moluccana (Suharti et al., 1991). Recently, short rotation plantation areas has been steadily

increasing throughout the country for a raw material of wood fibre, solid wood products and

also pulp and paper industry (Nik Muhamad and Paudyal, 1999). Although fast-growing

plantation has been taking place, timber from natural forest is still the main source of timber

product. However, log production in the tropics had decreased in 1980s due to decreasing

forest area (Firmanti et al., 2005). To address the issue of log supply the government has been

promoting the utilization of planted timber for industrial utilization. One advantage of using

the plantation species is that the wood properties can be modified at a very basic level

according to physical and mechanical desired to meet the demand for wood based industry

(Zink-Sharp and Price, 2006).

Most physical and mechanical properties of wood can be measure by destructive

testing. However, the technique is sometimes wasteful and time consuming. Development of

fast, simple, non-destructive and accurate methods apparatus become important in forest

product industry. Non-destructive evaluation (NDE) is a science of identifying the physical

1

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