An Elastoplastic-Damage Micromechanical Model and its Application to the Mechanical Analysis of SiC Fibre-reinforced Titanium Matrix Composite under Complex Stress States

An elastoplastic-damage micromechanical model based on the Finite Volume Directly Averaging Micromechanics (FVDAM) is developed for investigating the mechanical behaviour of continuous SiC fibre reinforced titanium matrix composite (SiC_f/Ti) under complex stress states. The proposed model is tangent formulated, i.e., plastic deformation and interface damage are integrated into the tangential modulus matrix. This feature makes the proposed model able to simulate the stress–strain responses under various loading cases including both proportional and nonproportional loading paths. The mechanical behaviour under the in-plane transverse stress is investigated, and good agreement is observed between results from the simulation and those from the experiment. The effects of out-of-plane stress and loading-path dependency on mechanical behaviour, including the initiation and evolution of interface damage and plastic deformation, are also discussed. The results indicate that the out-of-plane stress has pronounced effects on the micromechanical behaviour of SiC_f/Ti, and these effects are more significant in the nonproportional loading path than that in the proportional loading path.