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

Abstract

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. Parametric 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 estimates 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 efficient fracture analysis of CMCs.