Residual Tensile Strength Prediction on a Ply-by-Ply Basis for Laminates Containing Impact Damage

Abstract

Impact loading on composite laminates can cause surface or internal damage in the form of fiber breakage, delamination and matrix cracking. Such damage can reduce laminate tensile strength. In the work presented here, impact damage was modelled as part through-the-thickness damage and laminate residual strength was evaluated by ex amining the behavior of each individual ply of the laminate. A residual strength prediction procedure, proposed previously for laminates containing cut internal fibers, was used here for laminates containing impact damage. The prediction of laminate residual strength was performed based on 3-D finite element results in conjunction with a principal load carry ing ply failure criterion. The predicted residual strength agreed with the experimental data within the bounds of 0.85 to 1.08 times the experimental data, indicating the applicability of the procedure and the damage modelling technique.