Development of a Damage Mechanics Model for Fatigue Life Prediction of 2.5D Woven Composites

A continuum damage model (CDM) is proposed to predict the fatigue life of 2.5D woven composites (2.5DWC) with conformal or voxel meshing. Three independent damage variables of yarn fiber, yarn matrix, and matrix are defined to establish the constitutive relationship of woven composites with damage. The strain energy density, damage driving force, and damage evolution equation of material components are derived in the damage thermodynamics method, and the component correction stress is introduced to eliminate the effect of different meshing methods on fatigue life prediction. The model is implemented in ANSYS with the APDL language to simulate the fatigue failure process of 2.5DWC. The results show that the predicted fatigue life with conformal or voxel meshing differs by only 4.5% and shows agreement with the relevant experimental fatigue life.