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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

A Joke

A group of managers were given the assignment to measure the height of A flagpole. So they go out to the flagpole with ladders and tape measures, and they're falling off the ladders, dropping the tape measures - the whole thing is just a mess. An engineer comes along and sees what they're trying to do, walks over, pulls the flagpole out of the ground, lays it flat, measures it from end to end, gives the measurement to one of the managers and walks away. After the engineer has gone, one manager turns to another and laughs. "Isn't that just like an engineer! We're looking for the height and he gives us the length!"

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Lecture 3ADVANCED COMPOSITES

The modern advanced composites began with Boron filaments Boron provide high E not provided by glass:B: σ= 400 ksi E=65 msi ρ= 2.24 g/ccGl: σ= 500-600 ksi E=10-12 msi ρ= 2.5 g/ccBoron provide E required by many aircraftIn 1960’s Boron incorporated into F-15 and F-14

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Commercial Composites

FibersE GlassAsbestosResinThermosetsPolyestersPhenolicsEpoxiesThermoplasticsNumerous

Commercial Fabrication MethodsThermosetsContact Molding (Hand lay up, spray up)Matched (Compression) Die moldingResin injection molding RIMPultrusionFilament winding Continuous laminatingCentrifugal castingThermoplasticsInjection moldingTransfer moldingCompression moldingCold stampingRotational molding

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Major Materials

Major Reinforcement FibersGlass – E, S and S1Aramid: Kevlar 49, Kevlar 29Carbon/ GraphiteBoronOther fibers:

AluminaSilicon CarbideAlumina- Boria-SilicaBoron NitrideBoron CarbideTitanium Diboride

Major Resin1- ThermosetsEpoxiesPolyester (Thermosets)Vinyl EstersPolyimidesPhenolics2- ThermoplasticsNylonPolycarbonatePolyesters (thermoplastics)Polyimides

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Geometrical Aspects

Advanced Composites are made up of layers, piles, lamina or laminate. 0º (Unidirectional) is the starting point

Properties are dependent of:-Fiber diameter- Fiber length- Fiber length distribution- Volume Fraction of fiber (Vf)- Alignment and packing of fiber

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Hex vs. Square

3)(32 R

rV f

2)(

4 R

rV f

Vf is Volume of fibersThe max Vf occurs when fibers are touching.

For optimum properties, maximize Vf without fiber to fiber contact (why?)

Vc= Wc/ρc, Vr= Wlost/ρrVf= Wresidue/ρfVc= Vr+ Vf + (Vvoids)

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Modulus vs. Filament volume

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Can affect properties:

0° Tension -- little effectCompression– significantEnvironmental – significantFatigue – significantDelamination – significantImpact resistance – significant

Emmff VEVEE 1

(Rule of mixture for unidirectional modulus)

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Standard Code Elements

Each lamina is denoted by a number representing its orientation separated by a slash

Adjacent laminate with the same angle by a numerical subscript.

The laminate are listed in sequence from face to the other with brackets

Adjacent lamina of the same are denoted by a numerical subscript

A subscript T to the bracket indicates the total lamiate is shown

(0/ 45/ 90) → (50/40/ 10) means 50 % 0’s, 40 % 45’s, 10% 90’s.

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Positive and Negative Angles

Lamina of the same angle but opposite in sign, + and – are used. Positive angles are assumed clockwise looking toward the layup tool surface

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Positive and Negative Angles

Long FormThe latter is preferred because it can accommodate more numbers

Symmetric laminaStart at the face but stop at the symmetry. The subscript S indicates that only one-half of the laminate is shown

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Symmetric of Odd Numbers

Is the same as the even number of lamina except the center lamina listed last is overlined indicating that one half of it lies on either sides.

If odd laminate has additional of the same angle adjacent to the center lamina, a subscript is used with the overlined to indicate the number of “half lamina either side of the center.

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Appollo 11

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

X-15

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Golf Applications

100 Million Golfer around the world.

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

F-22

10 F-22 has been made so far. They are under testing and evaluation. By mid of 2005, 3 F-22 a month will be made. Bush requested 24 additional jets by the end of 2005. About 25% by wieght of F-22 is made of composites including carbon/epoxy. All the exterior skin is made of carbon fiber/bismaleimade (BMI) produced by automatic tape laying.

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Unmanned Helicopter TAG-M65 and TAG-M80

New unmanned helicopter is being made for tactical high risk missions. They are made of carbon/ epoxy prepregs, hand layed up in open mold. It can be carried by a foot soldier. Total length is 182 cm for M65 and the M80is about 15% longer

It can carry up to 20 kg load for 8 hours. It carries a Sielent Eye cost less than $ 15,000

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Quiz1

1- Advanced composites fiber materials are: Carbon, Kevlar, Boron, and:

A- GlassB- PolymerC- ResinD- E-glass

2- In metal, material selection only. But in composites: A- design onlyB- material selection onlyC- non of the aboveD- design creator and material selection

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Quiz1 Cont.

3- Of the fabrication method in advanced composite: A- CastingB- Autoclave MoldingC- ForgingD- bending and hammering

4- What make composite advantageous over metals besides the weight is:

A- colorB- oxidationC- design flexibilityD- corrosion resistance

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Quiz1 cont.

5- The modern advanced composites began with A- Boron filamentsB- Kevlar filamentsC- Carbon filamentsD- Glass filaments

6- Thermosets and Thermoplastic are:A- two types of fiberB- two names for the same itemC- two types of metalsD- two types of resin

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Quiz1 cont.

7- For optimum properties:A- lay up more 0 directional laminaB- maximize Vf without fiber to fiber contact C- lay up more multi-dimensional laminaD- add more resin

8- One that has significant effect on composites is A- corrosionB- oxidationC- delaminationD- shape

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Mechanical Engineering DepartmentAdvanced Composites

Dr. Talal Mandourah

Quiz1 cont.

9- The laminate [0/45/90]s, the subscript s meansA- symmetricB- same angles C- same materialD- surroundings

10- The laminate [45/0/902/30]T the subscript T means: A- torqueB- titaniumC- torsionD- total