Investigation on numerical analysis method of fatigue delamination damage of plane woven composites

Based on bilinear constitutive relationship, a cohesive model considering fatigue damage was established. Integrating with finite element analysis technology, the numerical analysis method of delamination propagation behavior of composite laminates was developed to simulate the mode II delamination propagation behavior of plane woven composite laminates under static and fatigue loading. The simulated load-displacement curve under quasi-static loading has good agreement with the experimental results. The simulated delamination propagation rate-strain energy release rate curve under fatigue loading is also in good agreement with the experimental results. Thus, the cohesive model considering fatigue damage has been validated. On this basis, the fatigue failure criteria for plane woven composites were established. Then the residual life prediction method of plane woven composite laminates with initial delamination damage was developed by integrating with the intralaminar progressive fatigue damage model. Using the developed method, the residual life and fatigue damage propagation of laminates with initial delamination damage were predicted, showing good correlation with the experimental results. In addition, the simulation results indicate that the fatigue damage initiates from the initial delamination damage which then propagates to the edges. The fatigue damage in both warp and weft directions appear early within the two layers of 0° adjacent to the initial delamination damage. And more damage occurs within the 0° layers than the 45° layers in general. Finally, the 0° layers show warp damage dominated failure mode while the 45° layers show weft damage dominated failure mode, and large area of damage appear at all the interlaminar interfaces.