Failure analysis of laminated composite pretwisted rotating plates

In this paper a finite element computational procedure is presented for the determination of first-ply failure strengths of pretwisted rotating plates subjected to centre point transverse load. The finite element model is based on the tensor polynomial failure criterion that contains the maximum stress, maximum strain, Tsai-Hill, Tsai-Wu and Hoffman failure criteria as special cases. A nine-noded three-dimensional degenerated composite shell element is developed and used for the present finite element formulation. Effects of transverse shear deformation and rotary inertia are included, Lagrange's equation of motion is employed to derive the dynamic equilibrium equation considering moderate rotational speeds for which the Coriolis effect is negligible. Finally, the static equilibrium equation is formulated after discarding the time-dependent terms. Failure load computations for rotating cantilever plates with nonlinear pretwist are carried out to investigate the effects of angle of twist, rotational speed and laminate configuration.