Abstract：A micromechanical model based on the periodic RVE technique is presented to predict the cohesive strength which is an important parameter in accurately modeling composite delamination via CZM (cohesive zone model) based FEM. By using major principal stress criterion to predict the crack initiation in cohesive layer, a relationship between cohesive and matrix strength is set up. A periodic displacement boundary condition has been presented on the assumption that the RVE is orthotropic in the sense of overall response. The cohesive strength of AS4/PEEK and T700/QY8911 laminates at various fibers cross angles are obtained by this model. The FEM simulations on mixed-mode-bending (MMB) and the six-point bending test are presented by applying CZM with the predicted cohesive strength. The numerical results are in fair agreement with experimental observation.
2012, Vol. 33 
