Effect of interfacial properties on the uniaxial tensile behavior of three-dimensional braided composites

In this study, a new nonlinear finite element model is presented to investigate the effect of interfacial properties on the uniaxial tensile behavior of three-dimensional (3D) braided composites. A cohesive zone model (CZM) is used to evaluate the debonding behavior of interface between yarn and matrix in this model. Taking account of interface damage mode and several damage modes of yarns and matrix within the braided composites, a numerical parametrical study is conducted to determine a set of reasonable interfacial properties and the failure mechanisms are revealed in the simulation process. In addition, the tensile modulus and strength of 3D braided composites are predicted and compared with the experimental results with a good agreement achieved. The calculated results show that the effect of interfacial elastic modulus on the tensile modulus of 3D braided composites is prominent, and the interface damage controlled by interfacial strength is one of the critical factors resulting in the nonlinearity of the longitudinal tensile stress-strain curves.