Presentation on theme: "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,"— Presentation transcript:
1A JokeA 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!"
2ADVANCED COMPOSITES Lecture 3 The modern advanced composites began with Boron filamentsBoron provide high E not provided by glass:B: σ= 400 ksi E=65 msi ρ= 2.24 g/ccGl: σ= ksi E=10-12 msiρ= 2.5 g/ccBoron provide E required by many aircraftIn 1960’s Boron incorporated intoF-15 and F-14
4Major Materials Major Resin Major Reinforcement Fibers 1- Thermosets Glass – E, S and S1Aramid: Kevlar 49, Kevlar 29Carbon/ GraphiteBoronOther fibers:AluminaSilicon CarbideAlumina- Boria-SilicaBoron NitrideBoron CarbideTitanium DiborideMajor Resin1- ThermosetsEpoxiesPolyester (Thermosets)Vinyl EstersPolyimidesPhenolics2- ThermoplasticsNylonPolycarbonatePolyesters (thermoplastics)
5Geometrical AspectsAdvanced Composites are made up of layers, piles, lamina or laminate.0º (Unidirectional) is the starting pointProperties are dependent of:Fiber diameterFiber lengthFiber length distributionVolume Fraction of fiber (Vf)Alignment and packing of fiber
6Hex vs. Square Vf is Volume of fibers The 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)
8Can affect properties: 0° Tension -- little effectCompression– significantEnvironmental – significantFatigue – significantDelamination – significantImpact resistance – significant(Rule of mixture for unidirectional modulus)
9Standard Code Elements Each lamina is denoted by a number representing its orientation separated by a slashAdjacent laminate with the same angle by a numerical subscript.The laminate are listed in sequence from face to the other with bracketsAdjacent lamina of the same are denoted by a numerical subscriptA 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.
10Positive 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
11Positive and Negative Angles Symmetric laminaStart at the face but stop at the symmetry. The subscript S indicates that only one-half of the laminate is shownLong FormThe latter is preferred because it can accommodate more numbers
12Symmetric of Odd Numbers 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.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.
15Golf Applications100 Million Golfer around the world.
16F-2210 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.
17Unmanned 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% longerIt can carry up to 20 kg load for 8 hours. It carries a Sielent Eye cost less than $ 15,000
18Quiz11- Advanced composites fiber materials are: Carbon, Kevlar, Boron, and:A- GlassB- PolymerC- ResinD- E-glass2- In metal, material selection only. But in composites:A- design onlyB- material selection onlyC- non of the aboveD- design creator and material selection
19Quiz1 Cont. 3- Of the fabrication method in advanced composite: A- CastingB- Autoclave MoldingC- ForgingD- bending and hammering4- What make composite advantageous over metals besides the weight is:A- colorB- oxidationC- design flexibilityD- corrosion resistance
20Quiz1 cont. 5- The modern advanced composites began with A- Boron filamentsB- Kevlar filamentsC- Carbon filamentsD- Glass filaments6- Thermosets and Thermoplastic are:A- two types of fiberB- two names for the same itemC- two types of metalsD- two types of resin
21Quiz1 cont. 7- For optimum properties: A- lay up more 0 directional laminaB- maximize Vf without fiber to fiber contactC- lay up more multi-dimensional laminaD- add more resin8- One that has significant effect on composites isA- corrosionB- oxidationC- delaminationD- shape
22Quiz1 cont. 9- The laminate [0/45/90]s, the subscript s means A- symmetricB- same anglesC- same materialD- surroundings10- The laminate [45/0/902/30]T the subscript T means:A- torqueB- titaniumC- torsionD- total