Compute the laminate strength

Question

Response to the following problem:

Consider a [0_s/90_s/45₂/ - 45₂]S with ply thickness t_k = 0.125 mm. The material is E-glass-polyester with fiber's Weibull shape parameter m = 6.2. Using the notation of carpet plots, this laminate has α = 0.4, β = 0.4, γ = 0.2. Compute:

1. the laminate F_PF strength F_xt. Note that the 904 lamina is the first to crack, thus defining FPF.

2. the laminate FPF strength Fyt. Note that the exterior 04 lamina is the first to crack, thus defining FPF.

3. recompute using in-situ strengths with transition thickness t_t = 1.2 mm.

4. Explain why F_{yt xt.}