Micromechanical Analysis of SiC/Ti6Al4V Composite Under Complex Stress State

Due to the complexity of micro-damage and boundary conditions in complex stress state, most micro-mechanical analyses of continuous SiC fiber-reinforced titanium matrix (SiC/Ti) composite mainly focus on in-plane stress state, which have not taken out-of-plane loadings into consideration. In this paper, a three-dimensional finite element model (FEM) has been developed to realize micro-mechanical analysis of SiC/Ti composite under complex stress state. The model is composed of a representative volume element (RVE). The effects of matrix plasticity, interface debonding and residual thermal stress are considered. The unified periodic boundary conditions and mixed-mode damage evolution law of the interface were adopted to make the RVE applicable in complex stress state. Single fiber push-out tests were carried out to estimate the interfacial shear strength. Good agreement between the simulation results and experiment data of uniaxial tension proved the model validity. The simulation results indicate that out-of-plane loadings have great influence on mechanical property degradation of SiC/Ti6Al4V composite. Besides, the interface debonding areas and matrix plasticity regions are no longer bilateral symmetrical under the effect of transverse shear load.