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Transcript of © GNU Su-Jin Kim Composite Material Science Composite( 복합재 ) Associate Professor Su-Jin...
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Composite(Composite( 복합재복합재 ))
Associate Professor Su-Jin Kim
School of Mechanical EngineeringGyeongsang National University
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Composit( 복합재 )
1. Fiber Reinforced Polymer (FRP) ( 섬유강화 )
2. Particle Reinforced ( 입자강화 )
3. Structure ( 구조강화 )
Particle-reinforced Fiber Reinforced Structural
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science 3
• Stacked and bonded fiber-reinforced sheets
- stacking sequence: e.g., 0º/90º
- benefit: balanced, in-plane stiffness
Structural Composite
• Sandwich panels
- low density, honeycomb core - benefit: small weight, large bending stiffness
honeycombadhesive layer
face sheet
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Particle Reinforced Composites I
SpheroiditeSteel
기지 : 페페페페
(ductile)
입자 :시맨타이트 (Fe3C)
(brittle)60 m
WC/Co 초경공구
기지 : 코발트 (ductile)
입자 : 텅스텐 (brittle, hard)Vm:
10-15 vol%! 600 m
자동차타이어Carbon black
기지 : 고무 (compliant)
입자 : 탄소 (stiffer)
0.75 m
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science 5
Concrete : 자갈 + 모래 + 시맨트
Reinforced( 강화 ) Concrete : 철근을 넣고 콘크리트를 부어 인장 응력에 견딜 수 있는 능력을 향상
Prestress Concrete : 철근에 인장 응력을 가한 상태로 콘크리트를 부어 경화시킨 다음 인장 응력을 제거 .
Particle Reinforced Composites II
Post tensioning : Place the tendons and nail anchors to the formwork, cast the concrete slab, remove the formwork, stress and anchor the tendons, then cut and grout the tendons with non-shrink grout.
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
• Elastic modulus, Ec, of composites:
- two approaches.
• Other Characteristics:
- Electric resistance, R: Replace E in equations with R. - Thermal conductivity, k: Replace E in equations with k.
lower limit:1
Ec= VmEm
+VpEp
c m m
upper limit:E = V E +VpEp
“rule of mixtures”
Data: Cu matrix w/tungsten particles
0 20 40 60 80 100
150
200
250
300
350
vol% tungsten
E(GPa)
(Cu) (W)
Particle Reinforced Composites III
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Fiber Reinforced Polymer (FRP)
FRP ( 복합재료 ) Fiber( 섬유 ) + Plastic matrix ( 모재 ) Fiber: Kevlar, Glass fiber, Graphite fiber, Boron Plastic matrix: Epoxy, Polyester
Process1. Impregnation: fiber+resin2. Molding3. Cure by heat & pressure
http://vimeo.com/13769356
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Fiber Reinforced Polymer, FRP
• Composites are made from two (fiber + plastic matrix) or more materials with significantly different properties and which remain separate on a macroscopic level.
• Reinforcements (fiber) improve strength, stiffness of plastic matrix.
http://www.youtube.com/watch?v=qEU9N7UNBWk&p=9B6D9EAE75875D9D
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Composite Usage
• Bow wings, tennis rackets, racing bicycles and skis are made of [Glass, Carbon fiber] + [Epoxy matrix] composit.
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Fiber materials
• Fibers are strong, stiff, have a high specific strength and specific modulus.
• But they are brittle, abrasive and lack toughness• Ex) Kevlar, Glass fiber, Graphite fiber, Boron.
stiffness/density
stre
ngth
/den
sity
•Steel, Aluminum
•Glass fiber
•Kevilar
•Graphite
•Boron
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Kevlar (Polymer fiber)
• Kevlar is a light, strong para-aramid synthetic fiber. • Kevlar has many applications such as racing tires,
because of its high tensile strength-to-weight ratio; 5 times stronger than steel on an equal weight basis.
Kevlar(yellow)+Graphite(black) Bulletproof helmet & vest
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Glass fibers ( 유리섬유 )
• Glass fiber is chipper than others.• Called Glass-fiber reinforced polymer (GFRP).
Glass fiber Fishing bloat
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Graphite fibers ( 탄소섬유 )
• Graphite fibres are more expensive; low density, high strength, and high stiffness.
• Called carbon-fiber reinforced polymer(CFRP).
Boing787
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Boron fibers
• High strength and stiffness in tension, compression and resistant to high temperatures.
• High density• Expensive
made with carbon and boron fibre
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Plastic matrix
Matrix (Resin) in reinforced plastics has 3 functions:1. Transfer the stress to the fibres2. Protect fibres against physical damage.3. Reduce propagation of cracks in the composite.
• Epoxy(80%), Polyester (cheap).
Carbon fiber + Epoxy
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Metal matrix• The advantage is it has higher resistance to elevated
temperatures and higher ductility and toughness.• Limitations are that it has higher density and makes
processing more difficult.
Fiber Matrix Application
Graphite Aluminum Helicopter, Tennis racket
Magnesium Satellite
Boron Aluminum Compressor blade
Titanium Jet-engine fan blade
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Properties of Fiber reinforced plastics
• Type and length of the fibres.• Volume fraction of the reinforcement.
© GNU Su-Jin Kim© GNU Su-Jin Kim
CompositeCompositeMaterial ScienceMaterial Science
Properties of Fiber reinforced plastics
• The highest stiffness and strength is obtained when fibres are aligned in the direction of tension force.