Development and validation of damage and failure models for the design of ceramic matrix composite components

Abstract

In this paper, test results for woven ceramic matrix composites (CMCs) based on an oxide matrix and oxide fiber are presented. Stress–strain curves under cyclic loading for different in-plane fiber orientations as well as strength values for different fiber orientations under tension and compression and under pure shear are presented. Based on the experimental data, a nonlinear damage model is derived which allows to determine the progressive degradation of the elastic moduli and the nonelastic remanent strain in a satisfactory manner. It has been implemented into the finite element code ANSYS and shows excellent convergence behavior. To predict the failure of CMC components, the failure mode concept proposed by Cuntze is extended to include friction effects due to tension and compression on the in-plane shear failure mode. The predicted failure onset matches the experimental data very well, whereas existing models like the max-stress or the Tsai–Hill criteria show larger deviations.