Abstract: Based on the microscopic structure of needle-punching quartz/quartz composite material, a representative volume elements considering the weaving structure was established. Then by introducing periodic boundary conditions and Voxel mesh, the finite element analysis model of the RVE is established. Assuming that the nonlinear mechanical behavior of needle-punching composites is mainly generated by the matrix, the effect of needling process is equivalent to the change of the matrix properties of composites. In order to do this, the properties of the matrix were modified using the J2 plastic model. Maximum principal stress criterion, Mises stress criterion and Tsai-Wu failure criterion were used as the failure criteria for each component. And, according to the different failure modes of fiber bundles, the stiffness reduction was conducted in the failed elements. The progressive damage process of needle-punching quartz/quartz composite material under uniaxial tensile load was simulated. The simulation results are in good agreement with the test curve, and the modified matrix shows the nonlinear characteristics of the needling composite well. On the basis of the above work, the influence of braiding angle on the tensile properties of the composite was analyzed. This dissertation would be helpful to guide the manufacturing and design of needle-punching composite material in the engineering.

Key words: needle-punching composites, 2-D braided, progressive damage, micromechanics, tensile properties, J2-plasticity model