Fatigue life prediction of fiber-reinforced titanium matrix composites

Abstract

A micromechanical model was developed to predict the fatigue life of SiC fiber-reinforced titanium matrix composites. The propagation of matrix cracks was modeled by calculating the stress concentration factor at the matrix crack tip in a fiber bridged center matrix crack. The residual stiffness was then predicted by using the partial-crack shear-lag model, and the post-fatigued tensile strength was predicted by using the load carrying capacity of fibers proposed previously for brittle matrix composites. Finally, the catastrophic failure and fatigue life of the composite was determined by Monte Carlo simulation. An integrated computer simulation code was developed to simulate the evolution of fatigue damage, degradation of mechanical properties, and to predict fatigue life. The predicted matrix crack propagation rates, residual stiffness, residual tensile strength, and fatigue life were also correlated with experimental results.