mechanical engineering department advanced composites dr. talal mandourah 1 a joke a group of...
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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