Damage onset on tow-placed variable stiffness composite laminates

Deflection and damage onset of variable stiffness composite laminated (VSCL) rectangular plates with curvilinear fibres, under static and dynamic loads, are investigated. The VSCLs here studied are characterized by the fact that, in each ply, the fibre-orientation angle changes linearly with respect to the horizontal coordinate. A recently developed p-version finite element, which follows third-order shear deformation theory (TSDT), is employed. Large deflections are considered, hence, the analysis is in the geometrically non-linear regime. To predict damage onset, Tsai-Wu criterion and an associated damage onset index, described in this paper as a safety factor, are used. It is shown that geometrical non-linearity affects stresses and the location of damage onset. VSCL and CSCL (constant stiffness composite laminated) plates subjected to static, dynamic, and impact loads, are compared.