Advanced Materials Ch4.ppt

COMPOSITES

Chapter 4

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Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering

Introduction A Composite material is a material system composed

of two or more macro constituents that differ in shapeand chemical composition and which are insoluble ineach other.

The history of composite materials dates back to early20th century. In 1940, fiber glass was first used toreinforce epoxy.

Applications: Aerospace industry Sporting Goods Industry Automotive Industry Home Appliance Industry

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Combination of two or more individual materials

Design goalObtain a more desirable combination of properties

(principle of combined action)e.g., low density and high strength

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Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 4

Ancient Mud bricks-makingMaking bricks with straw

The earliest man-made compositematerials were straw and mudcombined to form bricks for buildingconstruction. Ancient brick-makingwas documented by Egyptian tombpaintings.


https://wikicourses.wikispaces.com/Composite+materials+essay+%28HW+2%29


https://www.youtube.com/watch?v=dbywZ4PJ3QA

Composites


Classification of composites

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Composites consist of:

1. Combination of two or more materials Composite = matrix + fiber (filler):

• Matrix:

• material component that surrounds the fiber.

• Usually a ductile, or tough, material w/ low density

• Strength usually = 1/10 (or less) than that of fiber

• Examples include: thermoplastic or thermoset

• Thermoset most common (epoxy, pheneolic)

• Serves to hold the fiber (filler) in a favorable orientation.

• Fiber also known as reinforcing material aka Filler:

• Materials that are strong with low densities

• Examples include glass, carbon or particles.

2. Designed to display a combination of the best characteristics of each material i.e. fiberglass acquires strength from glass and flexibility from the polymer.

3. Matrix and filler bonded together (adhesive) or mechanically locked together!


Terminology/Classification

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• Composite:-- Multiphase material that is artificially

made.

• Phase types:-- Matrix - is continuous-- Dispersed - is discontinuous and

surrounded by matrix

Adapted from Fig. 16.1(a), Callister & Rethwisch 8e.


Composite Structural Organization: the design variations


Terminology/Classification

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• Dispersed phase:-- Purpose:

MMC: increase σy (yield stress)

CMC: increase Kic (Fracture Toughness)

PMC: increase E, σy,.-- Types: particle, fiber, structural

• Matrix phase:-- Purposes are to:

- transfer stress to dispersed phase- protect dispersed phase from environment

-- Types: MMC, CMC, PMC

metal ceramic polymer

Reprinted with permission fromD. Hull and T.W. Clyne, An Introduction to Composite Materials, 2nd ed., Cambridge University Press, New York, 1996, Fig. 3.6, p. 47.

woven fibers

cross section view

0.5mm

0.5mm


Matrix CompositesMatrix Materials: Polymer Matrix Composites PMC

There are two basic categories of polymer matrices: -Thermoplastics -Thermoset plastics

Roughly 95% of the composite market usesthermosetting plastics

Thermosetting plastics are polymerized in two ways: By adding a catalyst to the resin causing the resin to

‘cure’, basically one must measure and mix two parts ofthe resin and apply it before the resin cures

By heating the resin to it’s cure temperature

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Phenolic (phenols): good electrical properties,often used in circuit board applications

Epoxies: low solvent emission (fumes) uponcuring, low shrink rate upon polymerizationwhich produces a relatively residual stress-freebond with the reinforcement, it is the matrixmaterial that produces the highest strength andstiffness, often used in aerospace applications

Polyester (Polyester resin): most commonlyused resin, slightly weaker than epoxy but abouthalf the price, produces emission when curing,used in everything from boats to piping toCorvette bodies (combat ships).

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Common thermosetting plastics:


The reinforcement in a polymer matrix compositeprovides strength and stiffness that are lacking in thematrix.

The continuous reinforcing fibers of advancedcomposites are responsible for their high strength andstiffness.

The most important fibers in current use are glass,graphite, and aramid (Kevlar).

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Sanchez, Clément, et al. "Applications of advanced hybrid organic–inorganic nanomaterials: from laboratory to market." Chemical Society Reviews 40.2 (2011): 696-753.


https://youtu.be/6Dc88exXGpQ

carbon fiber composite car parts


Matrix CompositesMatrix Materials: Metal Matrix Composites MMC


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MMC-Applications

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Applications of MMC in Automotive: Some automotive disc brakes use MMCs. Early Lotus Elise models used

aluminum MMC rotors, but they have less than optimal heat properties andLotus has since switched back to cast-iron.

Modern high-performance sport cars, such as those built by Porsche, use rotorsmade of carbon fiber within a silicon carbide matrix because of its high specificheat and thermal conductivity.

3M sells a preformed aluminum matrix insert for strengthening cast aluminumdisc brake calipers, allowing them to weigh as much as 50% less whileincreasing stiffness.

Ford offers a Metal Matrix Composite (MMC) driveshaft upgrade. The MMCdriveshaft is made of an aluminum matrix reinforced with boron carbide.

Honda has used aluminum metal matrix composite cylinder liners in some oftheir engines, including the B21A1, H22A and H23A, F20C and F22C, and theC32B used in the NSX.

Toyota has since used metal matrix composites in the Yamaha-designed 2ZZ-GE engine which is used in the later Lotus Lotus Elise S2 versions as well asToyota car models, including the eponymous Toyota Matrix.

Porsche also uses MMCs to reinforce the engine's cylinder sleeves in the Boxsterand 911.

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https://youtu.be/mjytampRzRM

Light Weight Metal Matrix Composite Brake Drum


Matrix CompositesMatrix Materials: Metal Matrix Composites MMC


GE tests GE9X engine with ceramic matrix composites.Ground testing is underway on a GEnx engine that contains lightweight, heat-resistant ceramic matrix composite (CMC) components.


Composite Survey

Large-particle

Dispersion-strengthened

Particle-reinforced

Continuous(aligned)

Aligned Randomlyoriented

Discontinuous(short)

Fiber-reinforced

Laminates Sandwichpanels

Structural

Composites

Adapted from Fig. 16.2, Callister 7e.


• CMCs: Increased toughnessComposite Benefits

fiber-reinf

un-reinf

particle-reinfForce

Bend displacement

• PMCs: Increased E/ρ

E(GPa)

G=3E/8K=E

Density, ρ [mg/m3].1 .3 1 3 10 30

.01.11

10102103

metal/ metal alloys

polymers

PMCs

ceramics

Adapted from T.G. Nieh, "Creep rupture of a silicon-carbide reinforced aluminum composite", Metall. Trans. A Vol. 15(1), pp. 139-146, 1984. Used with permission.

• MMCs:Increasedcreepresistance

20 30 50 100 20010-10

10-8

10-6

10-4

6061 Al

6061 Al w/SiC whiskers σ(MPa)

εss (s-1)


• Examples:Adapted from Fig. 10.19, Callister & Rethwisch 8e. (Fig. 10.19 is copyright United States Steel Corporation, 1971.)

- Spheroidite steel

matrix: ferrite (α)(ductile)

particles: cementite(Fe3C) (brittle)60 μm

Adapted from Fig. 16.4, Callister & Rethwisch 8e. (Fig. 16.4 is courtesy Carboloy Systems, Department, General Electric Company.)

- WC/Co cemented carbide

matrix: cobalt (ductile, tough)

particles: WC (brittle, hard):

600μmAdapted from Fig. 16.5, Callister & Rethwisch 8e. (Fig. 16.5 is courtesy Goodyear Tire and Rubber Company.)

- Automobile tire rubber

matrix: rubber (compliant)

particles: carbon black (stiff) 0.75μm

Particle-reinforced Fiber-reinforced Structural


Classification: Particle-Reinforced

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Concrete – gravel + sand + cement + water- Why sand and gravel? Sand fills voids between gravel particles`

Reinforced concrete – Reinforce with steel rebar or remesh- increases strength - even if cement matrix is cracked

Pre-stressed concrete- Rebar/remesh placed under tension during setting of concrete - Release of tension after setting places concrete in a state of compression- To fracture concrete, applied tensile stress must exceed this

compressive stress


threadedrod

nut

Post-tensioning – tighten nuts to place concrete under compression


Classification: Fiber-Reinforced

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• Fibers very strong in tension– Provide significant strength improvement to the

composite– Ex: fiber-glass - continuous glass filaments in a

polymer matrix• Glass fibers

– strength and stiffness• Polymer matrix

– holds fibers in place – protects fiber surfaces– transfers load to fibers


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• Critical fiber length for effective stiffening & strengthening:

• Ex: For fiberglass, common fiber length > 15 mm needed

Classification: Fiber-Reinforced (v)Particle-reinforced Fiber-reinforced Structural

c

f dτ

σ>2

length fiber

fiber diameter

shear strength offiber-matrix interface

fiber ultimate tensile strength

• For longer fibers, stress transference from matrix is more efficientShort, thick fibers:

c

f dτ

σ<2

length fiberLong, thin fibers:

Low fiber efficiency

c

f dτ

σ>2

length fiber

High fiber efficiency


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Benefits of Long Fiber Reinforced


Composite Production MethodsPultrusion* Continuous fibers pulled through resin tank to impregnate fibers with thermosetting

resin Impregnated fibers pass through steel die that preforms to the desired shape Preformed stock passes through a curing die that is

precision machined to impart final shape heated to initiate curing of the resin matrix

Fig. 16.13, Callister & Rethwisch 8e.

*The term is a portmanteau word, combining "pull" and "extrusion".


Filament Winding Continuous reinforcing fibers are accurately positioned in a predetermined pattern to

form a hollow (usually cylindrical) shape Fibers are fed through a resin bath to impregnate with thermosetting resin Impregnated fibers are continuously wound (typically automatically) onto a mandrel After appropriate number of layers added, curing is carried out either in an oven or at

room temperature The mandrel is removed to give the final product

Adapted from Fig. 16.15, Callister & Rethwisch 8e. [Fig. 16.15 is from N. L. Hancox, (Editor), Fibre Composite Hybrid Materials, The Macmillan Company, New York, 1981.]


Pipe Fiber Reinforce Plastic Pipe


Classification: Structural

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• Laminates --- stacked and bonded fiber-reinforced sheets

- stacking sequence: e.g., 0º/90º- benefit: balanced in-plane stiffness

Adapted from Fig. 16.16, Callister & Rethwisch 8e.


• Sandwich panels-- honeycomb core between two facing sheets

- benefits: low density, large bending stiffness

honeycombadhesive layer

face sheet

Adapted from Fig. 16.18,Callister & Rethwisch 8e. (Fig. 16.18 is from Engineered MaterialsHandbook, Vol. 1, Composites, ASM International, Materials Park, OH, 1987.)


Special Issue: Composites for Ultralight Vehicles

Jenna OwenUniversity of Texas at Austin

ElectroPhen, 2008


Introduction Ultralight Strategy Materials Advanced Composites Hypercar Conclusion


Current model and disadvantages Steel model has been seen for almost a century. Cars are very heavy due to the weight of the steel. Current vehicles are not energy efficient.

85% of energy input is lost 1% of energy is used to move the passengers


Ultralight Strategy Mass decompounding is the key to an efficient

vehicle design.

Every 10% of weight reduction translates to a 7%increase in fuel economy.


Materials Light Steel (25-30% lighter)

Hydroform tubing used to create the autobody. Laser welding allows thin steel to be welded to thicker

steel. Aluminum (40% lighter)

New types of alloys and production techniques tested Advanced Composites (50-67% lighter)


Advanced Composites Composition

Polymers embedded into a “matrix of plastic” Composed of carbon, aramid, or similar fibers Composites durable, fatigue resistant, and reduce

noise and vibrations. Design

Materials formed into one unit or shell Aerodynamic drag reduced by 40-50% Rolling resistance reduced by 50%


Advanced Composites Safety

Materials are 20 times as stiff, 4 times as tough, andcan handle temperatures twice as high.

Composites can absorb 5 times more energy than anequivalent amount of steel.

Cost Advanced composites are expensive 1-2 orders of magnitude fewer parts Simple assembly and few tools required


Hypercar Incorporates ultralight technology along with a hybrid

electric drive system Travels 90-100 miles per gallon

Sundance Channel, 2008


Conclusion Ultralight technology will increase the energy

efficiency of future vehicles.

Advanced composites create light, safe, durable, andsuperefficient vehicles.


https://www.youtube.com/watch?v=KBZB3W7RG0M

Advanced Composite Technology Manufacturing


Projects:1. Simulation of Injection Molding with Moldex 3D2. The Future use of composites materials in transport.3. Use of Shape memory alloys for Solar tracking

system.

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Literature Reviews: IUG Library:

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http://library.iugaza.edu.ps/fulltext.aspx


http://www.sciencedirect.com/

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https://scholar.google.com

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Instructions for writing academic research Documentation ( Scientific paper, Research Proposal, technical Report)

Title of Research Project1. Abstract2. Motivation

Research Goals3. State-of-the-art

Literature Reviews4. Background

Ex: The Solar panel tracking system Ex: Shape memory alloys

5. Methodology6. Design and testing7. Conclusion8. References

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