Modeling of fatigue failure for SiC/SiC ceramic matrix composites at elevated temperatures and multi-scale experimental validation

Abstract

The fatigue failure of ceramic matrix composites at elevated temperatures was predicted using the micromechanics method. Multiple micro-damage models were developed to describe the evolution processes of matrix cracking, interface wear, and fiber fracture during fatigue loading. On this basis, the fatigue life was calculated. To validate the fatigue failure model, multi-scale experiments were conducted. In the macroscale, the S-N curve was obtained by the fatigue test. In the microscale, multiple in-situ measuring methods were developed through which the matrix crack density, the interfacial shear stress, and the percentage of fracture fibers were obtained. Both the macroscale and microscale experimental results were in good agreement with the predicted results. Therefore, the fatigue failure model developed in the present work is accurate.