Fatigue Damage in Metal Matrix Composites

In recent years the design and performance of aerospace vehicles changed due to enhancement and improvement in the design and the materials employed. Special consideration has to be given to the performance of the materials chosen for such vehicles. Titanium matrix composites (TMC) have been identified among the metal matrix composites as candidate materials capable of sustaining the arising loads while maintaining their structural integrity. Material behavior during fatigue loading has to be given special consideration since this loading condition is dominant during the flight regime. Material degradation due to fatigue loading is modeled using a micro-mechanical fatigue damage model for uni-directional metal matrix composites. The evolution of damage is considered at the constituent level by employing a damage criteria for each individual constituent. The overall material damage is obtained by using the Mori-Tanaka averaging scheme. A numerical implementation of the model is used to demonstrate its capabilities by presenting the analytical results for damage evolution in the fibers as well as in the matrix material for isothermal high cycle fatigue loading. Results for varying material and model parameters are also presented.