Numerical investigation into using coarse meshes to predict damage behaviors of laminated composites subjected to low-velocity impact

A high-efficiency numerical method is proposed for using coarse meshes to simulate the low-velocity impact behaviours of laminated composite structures with a relatively large number of layers. The interface strength corresponding to different levels of mesh refinement in the cohesive model is defined by deduced analytical expressions, the predictive capabilities of which are validated by measurements from double cantilever beam, end notched flexure and mixed-mode bending tests. A parameter known as saturation crack density is employed in damage evolution modelling to ensure the correct energy dissipation in coarse-mesh elements that may contain multiple cracks. Good agreement between the experimental and simulated results indicates the correctness of the proposed method for predicting impact mechanical responses and impact-induced damage. In addition, the results show that coarse-mesh models using the method proposed here not only yield consistent results, e.g., impact response curves and projected delamination area, with models with finer meshes but can also significantly improve computational efficiency.