Modeling first matrix cracking stress of fiber-reinforced ceramic-matrix composites considering fiber fracture

In this paper, the first matrix cracking stress (FMCS) of fiber-reinforced ceramic-matrix composites (CMCs) has been investigated using the energy balance approach considering fiber fracture. The shear-lag model combined with fiber failure model and interface debonding criteria has been adopted to analyze the stress distributions in CMCs. The relationships between the FMCS, interface debonding and slipping, and fiber fracture have been established. The effects of fiber volume fraction, interface shear stress, interface debonded energy, fiber Weibull modulus, and fiber strength on the FMCS, interface debonded length and fiber broken fraction have been analyzed. The experimental FMCS of three different CMCs, i.e., SiC/borosilicate, SiC/LAS, and C/borosilicate, with different fiber volume fraction have been predicted. It was found that the fiber/matrix interface possesses strong bonding in SiC/borosilicate and SiC/LAS composites, and weak bonding in C/borosilicate composite.