Micromechanical analysis of fiber-reinforced ceramic matrix composites by a hierarchical quadrature element method

This work performed stress predictions of unidirectional fiber-reinforced ceramic matrix composites (CMCs) subjected to longitudinal tension using a hierarchical quadrature element method (HQEM). The HQEM is a p -version finite element method that can present highly accurate results using only a few sampling points. Para-metric analysis was conducted to investigate the sensitivity of the HQEM model to interface properties and the detailed process of determining the optimal interface parameters for micromechanical analysis of damaged CMCs has been elaborated. By comparison with the analytical results based on the classical shear-lag model which is commonly adopted to analyze the stress distributions of the damaged fiber-reinforced CMCs, the HQEM esti-mates of fiber and matrix stress distributions were validated. For uniformly loaded SiCf/SiC composites with a single matrix crack, the micromechanical behaviors of three typical cases during failure process, namely, interface perfectly bonded, interface debonding and fiber failure were analyzed, illustrating the characteristics of CMC failure and providing insight into the mechanisms relating the microstructural behavior to global failure. The present work offers the foundations of the extension of a promising approach for highly accurate and effi-cient fracture analysis of CMCs.

Automated summary

This study performed stress predictions of fiber-reinforced ceramic matrix composites using a hierarchical quadrature element method. The sensitivity of the model to interface properties was investigated, and the process of determining optimal interface parameters for micromechanical analysis was elaborated. The accuracy of the model was validated by comparing with analytical results, and the microstructural behavior and mechanisms related to global failure were analyzed. This work establishes the foundations for a promising approach for fracture analysis of composites.