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P6.6. A [0/90/+45]s T-300 carbon fiber-epoxy laminate is subjected to the follow

ID: 2086996 • Letter: P

Question

P6.6. A [0/90/+45]s T-300 carbon fiber-epoxy laminate is subjected to the following in-plane loads: Nrx- 1000 lb/in., Ny.-200 lb/in., and Nxy500 lb/in. Each ply in the cured laminate is 0.006 in. thick. The basic elastic and ultimate properties of the material are as follows: E 20 x 106 psi, E2 1.3 x 10psi, G121.03 X 10° psi, v120.3, a.-0.0085, ??.c-0.0098, ?? 0.0045 ??'c 0.0090. and M.Ts 0.015. Using the maximum strain theory, determine whether any of the laminas in this laminate would fail at the specified load.

Explanation / Answer

Given that,

   Nxx = 1000 lb/in

   Nyy = 200 lb/in

   Nxy = -500 lb/in

    T = 0.006 in

E11 = 20 x 106 Psi

E22 = 1.3 x 106 Psi

G12 = 1.03 x 106 Psi

V12 = 0.3

U =?

U = 1/ 2E [ Nxx2 + Nyy2 +Nxy2 - 2x0.3( NxxNyy + NyyNxy+NxyNxx)]

     = 1/2 x 20 x 106 [ 10002 + 2002 + 5002 - 0.6( 1000x200 - 200x500 -500x1000)]

    = 0.03

U for the next E value is

     = 1/ 2 x 1.3 x 106 [ 10002 + 2002 + 5002 - 0.6( 1000x200 - 200x500 -500x1000)]

     = 0.58

U for the next value of E

     = 1/2 x 1.03 x 106 [ 10002 + 2002 + 5002 - 0.6( 1000x200 - 200x500 -500x1000)]

     = 0.74

This would fail at the first set.