Modeling of compressive failure due to kinking in cross-ply laminates under cylindrical bending

The compressive failure of laminated composite plates with orthotropic or transversely isotropic layers under cylindrical bending is modeled by a steady state kink propagation localized failure mode. For fixed displacement boundary conditions the virtual work principle leads to an energy balance between the reduction of the strain energy due to kink propagation and the dissipated energy at the kink process zone. The reduction in the strain energy is found by utilizing an exact elasticity solution of cylindrical bending for orthotropic laminates derived by Pagano, modified to also include transversely isotropic layers. The resulting critical compressive load depends on the macro-geometry and boundary conditions, through the elasticity solution, and on the micro-mechanical parameters of the kink zone, through the evaluation of the dissipated energy at the kink process zone. The effect of geometry and material properties on the critical compressive load, at which kinking will occur, is presented for cross-ply laminates under four-point bending and correlation with experimental results for carbon/thermoplastic laminates is discussed.

Modeling of compressive failure due to kinking in cross-ply laminates under cylindrical bending Conference Paper