Mesoscale progressive damage and strength analysis of three-dimensional braided composites under tension

Three-dimensional (3D) braided composites have broad development prospects in various industries. This paper establishes a real parametric finite element model (FEM) to conduct progressive damage analysis and strength prediction for 3D braided composites. 3D FEM is established with consideration of the cross-section deformations and surface contact of adjacent braiding yarns. Subsequently, 3D Hashin and maximum stress failure criteria are separately implemented as initiation damage criteria for yarn and matrix. Moreover, different damage modes are employed to predict progressive failure process of yarn and matrix. Lastly, the relationship of braiding parameters to strength was thoroughly analyzed and numerical predictions generated which were validated through the experimental data. The results demonstrate that stress–strain curves and strength values are closely related to the braiding angle and the fiber volume fraction. Moreover, damage evolutions show shear bands predominately occur in the surface of yarns for small braiding angles, while for large braiding angles, it mainly occurs in the yarn/yarn interface. The yarn damage for composites of low fiber volume fraction occurs on yarn/yarn junction and then extends to entire yarns, while for high fiber volume fraction, it takes place directly on entire yarns.