Progressive damage simulation and strength prediction of three-dimensional and six-directional braided composites

Based on the meso-structure of three-dimensional and six-directional braided composites and assuming that the cross-section of weft yarn on the sixth direction was diamond, a representative volume element (RVE)-based micromechanical damage model was presented to predict the damage propagation and strength of three-dimensional and six-directional braided composites. The stress-strain relation of three-dimensional and six-directional braided composites was simulated by using failure criteria proposed by Linde and the periodicity boundary condition. The progressive damage of three-dimensional and six-directional braided composites was studied subjected to longitudinal tensile loading, and ultimate strength of the sample was obtained. Furthermore, the changing characteristics of mechanical properties with the material parameters of braided composites were discussed. The results show that the main factor to break the three-dimensional and six-directional braided composites is longitudinal tensile breakage of axial yarns, and the FEM results are in a good agreement with experimental data, which confirms the effectiveness of the model and provides a basis for the analysis of mechanical properties.