Bi-interfacial debonding of coated fiber reinforced composites under fatigue load

By secondary development of the commercial finite element package ANSYS, the present work characterizes the bi-interfacial debonding (fiber/coating and coating/matrix) behavior of coated fiber reinforced composites under tension–tension cyclic load. In the finite element analysis of the double shear-lag model, ordinary mesh and the relationship between stress intensity factor and energy release rate are utilized in order to avoid concerning the singularity of crack tips. Based on the results of strain energy, the debond growth in one cycle is derived from the combined implementation of difference approximation; defining debond criterion and crack propagation law by programming. With the simulation of total fatigue life, the effects of strength and thickness of coating materials on the bi-interfacial crack growth are studied, and two-interface coupling in debonding is found. Furthermore, non-uniform damage of coating materials and other fatigue properties are also discussed.