human skull is a sandwich structure, made up of two outer faces of dense cortical bone, separated by a low density, foam-like layer of trabecular...

 human skull is a sandwich structure, made up of two outer faces of dense cortical bone, separated by a low density, foam-like layer of trabecular bone. The thickness of each shell of cortical bone, t, is 1.5mm. The thickness of the core of trabecular bone, c, is 8mm. The relative density, ρ∗/ρs , of the trabecular bone is 0.2. The Young's modulus of the solid bone is . Calculate the contribution of the core about its own neutral axis to the flexural rigidity,(EI)eq per unit width of the skull