Numerical investigations of perforated laminates in the presence of residual ply stresses

Finite element-based first-ply failure strength investigations of perforated laminates in the presence of residual ply stresses are presented. Unit-cell models are applied, where inter- and intra-laminar failures as well as free-edge effects are taken into account on the ply level. The critical stress states contain constant and variable stress parts, which mean that nonradial loading paths are considered. Failure envelopes are computed for different layups and residual stress levels. This way the strength evaluation of structures containing perforated laminates can be performed on the macroscopic, i.e. structural, level.