mae482&582 WHY COMPOSITES

mae482&582 WHY COMPOSITES - Willing to pay $100-200/lb...

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WHY COMPOSITES? Application to aero structures, per Colin Adam 10/1/92 (“outdated, but the ideas are good”) Mg Al Ti Maraging STL Gr/Ep, 60 v% Cost $/lb 3 2 12 7 25 Density ρ lbf/in 3 0.07 0.1 0.14 0.3 0.06 Ult. Strength σ u , 10 3 psi 67 70 140 330 500 σ u / ρ 910 700 1,000 1,100 8,000 σ u /( ρ $) 303 350 83 156 320 Toughness K 1c 10 35 100 200 20 (damage) K 1c / ρ 140 350 555 667 320 K 1c /( ρ $) 97 175 46 95 13 E 10 6 psi 6.7 10 14 30 36 (woven cloth) E/ ρ 95 100 100 100 600 E/( ρ $) 32 50 8 13 24 ρ affects 100% of structure σ u affects 30% of structure (strength driven) E affects 15% of structure (stiffness, buckling) K 1c affects 20% of structure (fracture toughness, “damage tolerance”)
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Unformatted text preview: Willing to pay $100-200/lb of weight saved; Total cost = materials costs + design + machining + maintenance + For metals, talk buy/fly ratio (much machining); for composite, largely net shape manufacturing Recycling is an issue; Al easier than most composites. Older technology: A300-B4 has 4 % composites, 4% Ti, 12% STL, 77% Al (!), 3% other (Aerospace America, 8/06) Newer technology: Boeing 787 has 50% composites, 10% STL, 20% Al, 15% Ti, 5% other (Boeing http://www.boeing.com/commercial/787family/programfacts.html 8/06)...
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