Thermal-mechanical-oxidation coupled first matrix cracking stress model for fiber reinforced ceramic-matrix composites

In this work, we research the combined influence of residual thermal stress, interface debonding and oxidation, and temperature on first matrix cracking stress of fiber reinforced ceramic-matrix composites (FRCMCs). Based on the shear-lag theory, the axial stress distribution of matrix and fiber considering interface oxidation and residual thermal stress is given, and we propose a criterion for interface debonding. Then, a thermal-mechanicaloxidation coupled first matrix cracking stress model is proposed for FRCMCs, according to energy balance approach. Reasonable agreement is obtained between the model predictions and available experimental results of SiCf/RBSN and SiCf/SiC composites. Moreover, the effects of some key material parameters and oxidation time on first matrix cracking stress are analyzed quantitatively by the model. This research offers a quantitative tool for evaluating and predicting the matrix cracking behavior of FRCMCs under thermal-mechanical-oxidation coupled environment.

Automated summary

This research investigates the combined influence of residual thermal stress, interface debonding and oxidation, and temperature on the first matrix cracking stress of fiber reinforced ceramic-matrix composites. A thermal-mechanical-oxidation coupled first matrix cracking stress model is proposed and validated with experimental results, offering a quantitative tool for evaluating the matrix cracking behavior of FRCMCs.