Tensile Behavior of Ceramic-Matrix Composites

Abstract

Under tensile loading, the fiber-reinforced ceramic-matrix composites (CMCs) exhibit obvious nonlinear behavior, due to the multiple damage mechanisms of matrix multicracking, fiber/matrix interface debonding and fibers failure. In this chapter, the micromechanical approach to predict the tensile stress–strain curves of fiber-reinforced CMCs is developed. When matrix cracking, fiber/matrix interface debonding, and fibers failure occur, the shear-lag model is adopted to analyze the microstress field of the damaged fiber-reinforced CMCs, i.e., the fiber and matrix axial stress distributions. Combining the shear-lag model with damage models of matrix statistical cracking, fracture mechanics fiber/matrix interface debonding criterion and Global Load Sharing (GLS) fibers failure criterion, the matrix cracking spacing, fiber/matrix interface debonding length, and fibers broken fraction are determined. The tensile stress–strain curves of fiber-reinforced CMCs corresponding to different damage stages are modeled. The tensile stress–strain curves of unidirectional, cross-ply, 2D, and 2.5D woven CMCs are predicted.