Mechanical analysis of three-dimensional braided composites by using realistic voxel-based model with local mesh refinement

The elastic and failure analysis of three-dimensional braided composites is conducted by using realistic geometry model with local mesh refinement. The realistic geometry model is reconstructed by using micro computed tomography images. The voxel meshes are utilized to overcome the difficulties of mesh discretization for realistic geometry model of three-dimensional braided composites with complex meso-geometrical configurations. In order to improve the computational efficiency, the local voxel meshes at the braid yarn boundaries are refined to capture the detailed geometries of braid yarn and reduce the number of mesh. The stress averaging technique is applied to alleviate the local artificial stress spurious introduced from voxel meshes at braid yarn boundaries. Three kinds of computation models are used to predict the tensile properties of the braided composites, which are also compared with experimental results. The effects of braid yarn twist angle and mesh sizes on the predicted tensile behavior of the braided composites are studied further. A systematic way is provided to analyze mechanical properties of three-dimensional braided composites by using realistic voxel-based model.