A multiscale damage prediction model for the thermal shock of carbon fiber-reinforced silicon carbide matrix composites

In this study, under the heating rate of 1300 °C/min, the thermal shock tests of 2D C/SiC composites with different thermal shock cycles and temperature differences (680 °C, 980 °C, 1280 °C) were carried out. Based on thermal shock damage mechanisms, a two-step residual properties prediction model using thermal-mechanic-oxygen coupling and cross-scale methods was established. The damage field calculation and residual properties prediction were carried out according to the thermal shock condition in the first. The test results show that matrix cracking caused by thermal gradient stress, interfacial debonding caused by thermal mismatch and fiber failure caused by oxidation are the main reasons for thermal shock damage of 2D C/SiC composites. The prediction results show that the residual strength, stiffness and stress–strain curve of the thermal shock obtained by the prediction have little difference from the test results, which reflects the accuracy of the prediction model.