Compute the torsional stiffness (GJR) of the beam in given Example.

Example

Compute the bending stiffness of a cantilever I-beam (Figure below) of length L = 30 cm, subjected to a tip-shear force V_z = 445 N. The dimensions of the beam are: h = 2.5 cm, b = h/2, t = h/16. The material is Kevlar-epoxy with the following elastic constants: E₁ = 76.0 GP a, E₂ = 5.56 GP a, G₁₂ = 2.30 GP a, ν₁₂ = 0.34. The lay-up sequence is [±30/0]S, six laminae (n = 6), with lamina thickness t_k = t/6.