Finite element analysis of mechanical properties of 3D five-directional braided composites

As for 3D five-directional rectangular braided composites, a three-dimensional (3D) finite element model (FEM) based on a representative volume element (RVE) is established under the periodical displacement boundary conditions, which truly simulates the spatial configuration of the braiding yarns and the axial yarns. The software ABAQUS is adopted to study the mechanical properties and the meso-scale mechanical response of the composites. The effects of the braiding angle and the fiber-volume fraction on the engineering elastic constants are investigated in detail. The predicted effective elastic properties are in good agreement with the available experimental data, demonstrating the applicability of the FEM in the case of tension in the primary loading direction z. By analyzing the stress distribution and deformation of the model, it is proved that the RVE-based FEM can successfully predict the meso-scale mechanical response of 3D five-directional braided composites containing periodical structures.