Numerical Analysis of a Ceramic Matrix Composites with Strain Induced Damage Using Finite Element Method

A computationally efficient FE model has been developed to predict the mechanical behavior of ceramic matrix composites with strain-induced damage. The effects of different damage modes and their interactions on mechanical behavior have been considered. The non-linear longitudinal material properties are discretised to a multi-linear elastic curve. The constitutive equations for orthotropic materials are used to update the stresses for each increment of the analysis. The model is implemented by a Finite Element package, ANSYS with a user defined subroutine, UMAT. In all analyses, the expected mechanical behavior has been obtained. Strain induced damage modes and their interactions are modeled using the finite element method for Ceramic Matrix Composites (CMC) tows and 0 degrees/90 degrees laminates. For both situations, bi-axial straining is addressed, together with the degradation of Young's modules and Poisson's ratios. In all cases, the expected stress-strain behavior is calculated.