Trans-scale elastic–plastic damage analysis of 3D tubular braided composites with void defects

Three-dimensional (3D) tubular braided composites exhibit irreversible plastic deformation and nonlinear behavior due to the void defects and plastic effects of the matrix. Therefore, this paper establishes an elastic–plastic damage constitutive model of 3D tubular braided composites with defects, which is coupled with plastic effects and damage accumulation. Firstly, 3D tubular braided composite models with defects are established by sequential trans-scale analysis method to transfer the mechanical properties of the component materials. Then, according to the brittleness of the fiber or yarn and the plasticity of the matrix, the elastic and elastic–plastic damage model of the fiber and the matrix are established, respectively. On this basis, an interface element is established to characterize the mechanical properties of the interface with the tractor-separation constitutive model. Finally, the finite element results of the axial compression properties of 3D tubular braided composites coupled with the porosity and plasticity of the matrix, the longitudinal shear nonlinearity of the yarn and the bilinear constitutive relationship of the interface are in good agreement with the experimental results.