Numerical investigation on the variation of compressive failure mechanisms in unidirectional carbon fiber reinforced polymer

This paper presents a study on the variation of compressive failure mechanisms in carbon fiber reinforced polymer (CFRP) as well as the effects of material properties and structure parameters on the compressive strength in different failure mechanisms. A two-dimensional microscale model is developed to simulate numerically the compressive process of CFRP with local structure imperfections. The fiber kinking can be induced by either the interfacial failure or the matrix yielding depending on the interfacial strength of carbon fibers. CFRP with lower interfacial strength can exhibit wider kink band. Higher Young’s modulus of matrix, yield strength of matrix or misalignment level causes the failure mechanisms variation to occur at higher interfacial strengths, while the fiber diameter affects the failure mechanism variation in the opposite way. Furthermore, the compressive strength is found to be sensitive to the variation of matrix properties in the matrix-driven failure and to the fiber diameter in the interface-driven failure. These findings indicate that the strategies for the compressive strength enhancement can be different according to the compressive failure mechanisms.