Tensile properties of fiber reinforced epexy resin composite with ply splice structures

In order to understand the mechanical property of the fiber reinforced epexy resin composite with ply splice structure and get strong ply splice structures, the tensile properties of three kinds of unidirectional CF/EP with ply splice structures were tested. The tensile specimens were monitored during the loading process to analyze the fracture process, and finite element method (FEM) was used to study the character of the stress distributions when the ply splice structures were under a tensile load. All the CF/EP materials were prepared through vacuum assisted resin transfer molding (VARTM) process. The results show that, inducing ply splices into CF/EP materials, the tensile strength decreases evidently. Due to the ply splice, stress concentrations occur, and the initial fracture happens in the ply splice position, leading to the final fracture on the interfaces between different plies. The interlaminar shear stress and the tensile stress in the through-thickness direction near the ply splice position are the key factors leading to the initial failure. In order to get stronger ply splice structures, symmetric structures should be adopted.