Mechanical behavior analysis of 3D braided composite joint via experiment and multiscale finite element method

This study investigates the mechanical behavior of 3D braided composite truss joints through experiments and a multiscale finite element method. Unit cell models of 3D braided composites, which take into account the yarns, matrix and interface, are established to predict the mechanical properties. A novel damage model based on a modified Tsai-Wu criterion is developed to characterize the progressive damage of the composites. Excellent loading capacities of the joints suggest that 3D braided composites are applicable to complex structural components. The simulation results of the load-displacement curve, strain process, and the damage phenomenology are in good agreement with experimental data. This study also discusses the influence of braiding angle and fiber volume fraction on the loading capacity. The decrease in braiding angle and increase in fiber volume fraction of the composites can improve the loading capacity of the joints.