Composites in Aerospace Industry

7/27/2019 Composites in Aerospace Industry

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Composite materials Two or more constituent materials withsignificantly different physical or chemicalproperties, that when combined, produce amaterial with characteristics different from theindividual components. The individual

components remain separate and distinctwithin the finished structure.

Typical engineered composite materialsinclude:• Composite building materials such as

cements, concrete• Reinforced plastics such as fiber-reinforced

polymer • Metal Composites• Ceramic Composites (composite ceramic

and metal matrices)



Composition of Composites

Fiber/Filament Reinforcement Matrix Composite



Use of composites in the aerospace industry has increaseddramatically since the 1970s. Traditional materials - aluminium, steeland titanium.

Benefits of composites - reduced weight and assemblysimplification.The performance advantages by reducing the weight of aircraft

elements has been the major impetus for military aviationcomposites development.

Reduced production and maintenance costs has proven to be amajor factor in the push towards composites. Composites are alsobeing used increasingly as replacements for metal parts on olderplanes.

New aircraft utilize what would be considered high performancecomposites in marine terms. These include carbon, boron andaramid fibres combined with epoxy resins.



The above figure shows current and projected expenditures foradvanced composite materials in the aerospace industry.



Examples of specific aerospace composites

development programs :• Lear Fan 2100: The Lear Fan uses approximately 1880 pounds of carbon,

glass and aramid fibre material.• Beech Starship• Boeing: Composites are widely used in aircraft interiors to create

luggage compartments, sidewalls, floors, ceilings, galleys, cargo linersand bulkheads. Fiberglass with epoxy or phenolic resin utilizing

honeycomb sandwich construction gives the designer freedom tocreate aesthetically pleasing structures while meeting flammability andimpact resistance requirements.

• Airbus• Advanced Tactical Fighter (ATF): Advanced composites enable the ATF

to meet improved performance requirements such as reduced drag, low

radar observability and increased resistance to temperatures generatedat high speeds. The ATF will be approximately 50% composites by weightusing DuPont's Avimid K polyamide for the first prototype.

• Navy Fighter Aircraft (F-18A): The wing skins of the F-18A represented thefirst widespread use of graphite/epoxy in a production aircraft.

• Osprey Tilt-Rotor (V-22): Up to 40% of the airframe consists of composites,

mostly graphite fibres in 3501-6 epoxy (both from Hercules).



Why use plastics?

• Strength to weight ratio

• Part count and manufacturing operations reduction

•

Flexibility

• Electromagnetic transparency

• Corrosion resistance

• Smooth contours



Advantages• Weight reduction (approx. 20-50%)• Corrosion resistance•

Fatigue resistance• Tailorable mechanical properties• Sales through offset• Lower assembly costs (fewer, fasteners,

etc.)

Disadvantages• Some higher recurring costs• Higher nonrecurring costs• Higher material costs• Nonvisible impact damage• Repairs are different than those to metal

structure• Isolation needed to prevent adjacent

aluminium part galvanic corrosion



Market SectorsCommercial

Largepassenger

and freightaircraft for civilian use

Military

Militaryaircraft both

fighter andbomber aircraft

Rotary

Helicoptersfor both

civilian andmilitary use

Business jetsand small

planes

Space

Satellites,manned

andunmannedspacecraft

Missiles &Weapons



PMMA



T y p i c

a l

T h e r m o p l a s t i c s

PMMAPolymethylmethacrylate

PC Polycarbonate

PTFE and other fluoroplastics

PA Polyamides(nylons)

PEEK Polyetherketone

PEI Polyetherimide

PAI Polyamide-imide

PAA Polyarylamide

PSS Polyphenylene sulfide

PPSU Polyphenylsulfone

PVF Polyvinylidene fluoride

POM Polyoxymethylene

Fibers used

Carbongraphite fiber reinforcement

Glass fiber reinforcement

Aramid fiber

reinforcement

Composite

matrix used

Polyester resins

Epoxy resins



Carbon-fiber-reinforced polymer

Extremely strong and light fiber-reinforced polymer The polymer is most often epoxy, but other polymers, such aspolyester , vinyl ester or nylon, are sometimes used.

The strongest and most expensive of these additives, carbonnanotubes, are contained in some primarily polymer baseballbats, car parts.

It has high strength-to-weight ratio and very good rigidity is ofimportance.

Rudder of A310 AirbusAdvantages over a traditional rudder made from sheet aluminiumare:

25% reduction in weight95% reduction in components by combining parts and formsinto simpler moulded parts.Overall reduction in production and operational costs,economy of parts results in lower production costs and theweight savings create fuel savings.

http://en.wikipedia.org/wiki/Fiber-reinforced_polymer

http://en.wikipedia.org/wiki/Polymer

http://en.wikipedia.org/wiki/Epoxy

http://en.wikipedia.org/wiki/Polyester

http://en.wikipedia.org/wiki/Vinyl_ester

http://en.wikipedia.org/wiki/Nylon

http://en.wikipedia.org/wiki/Carbon_nanotubes


http://en.wikipedia.org/wiki/Strength-to-weight_ratio








http://en.wikipedia.org/wiki/Nylon

http://en.wikipedia.org/wiki/Vinyl_ester

http://en.wikipedia.org/wiki/Polyester

http://en.wikipedia.org/wiki/Epoxy

http://en.wikipedia.org/wiki/Polymer






Glass fibre reinforced polymers

Glass fibers are useful thermal insulators because of their highratio of surface area to weight. However, the increasedsurface area makes them much more susceptible to

chemical attack. By trapping air within them, blocks of glassfiber make good thermal insulation

Advantages this has over cast aluminium manifolds are:Up to a 60% reduction in weightImproved surface quality and aerodynamics

Reduction in components by combining parts and formsinto simpler moulded shapes.

Automotive gas and clutch pedals made from glass fibrereinforced PA 66 (DWP 12 – 13)

In contrast to carbon fiber , glass can undergo more elongation before itbreaks. There is a correlation between bending diameter of the filamentand the filament diameter

http://en.wikipedia.org/wiki/Thermal_insulation

http://en.wikipedia.org/wiki/Carbon_fiber

http://en.wikipedia.org/wiki/Carbon_fiber

http://en.wikipedia.org/wiki/Thermal_insulation



Aramid Fibers

Aramid fibers are a class of heat-resistant and strong synthetic fibers.They are used in aerospace and military applications, for ballisticrated body armor fabric and ballistic composites, in bicycle tires, and asan asbestos substitute.

i i f i i

http://en.wikipedia.org/wiki/Synthetic_fiber

http://en.wikipedia.org/wiki/Bulletproof_vest

http://en.wikipedia.org/wiki/Cloth

http://en.wikipedia.org/wiki/Asbestos

http://en.wikipedia.org/wiki/Asbestos

http://en.wikipedia.org/wiki/Cloth







Future applications of plastics in aerospaceNanocompositesNanocomposites offer huge benefits• Lighter and stronger materials – nanotechnology has the potential toincrease strength and heat resistance in both conventional thermoplasticsand composites.• Self-clean coatings – nanotechnology can be used to produce self-cleaning coatings for flight surfaces to reduce drag and improve fuelefficiency.• Abrasion resistant coatings – aerospace glazing can suffer from abrasion

during use and nanotechnology can produce abrasion resistant coatings toprolong life and visibility.

Light weight remotesThe growing use of remote controlled surveillance craft has been enabled bythe ability of plastics materials to reduce weight and to increase flight times.

This is a relatively new area for aerospace and the use of plastics has beenan enabling technology for this area.

Rapid manufacturingRapid manufacturing techniques are now being developed for theproduction, not simply of prototypes, but also for the series production of

parts. Rapid manufacturing allows rapid testing and development to achievethe best design for virtually non-existent tooling costs.



Potential concernsFire, smoke and toxicityThe response to fire is not a simple flammability issue, but is a combined issue

of flame, smoke, and toxicity (FST). Compliance with FST regulations ismandatory and one of the key issues in the use of plastics. Engineeringplastics generally have better FST response than the commodity plastics.

Fracture and failure issuesHigh-strength composites can suffer invisible damage due to impact that can

affect their long-term performance. The aim is to reduce impact damageand to prevent any potential cracks from spreading.

RecyclingAlmost all of the materials used in aerospace can be easily recycled usingcurrently available technology. However, for composite materials, the

recycling technologies are still new and developing rapidly. One of the mostpromising technologies is the use of pyrolysis, high temperature processingwithout the presence of oxygen. Pyrolysis offers an opportunity to take wastecomposite materials and to recycle these into valuable feedstock (eg. Gases,oils, waxes, char, etc.) for new composite materials.

Composites in Aerospace Industry

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