In-situ crack opening displacement of C/SiC under cyclic loading

Abstract

In this paper, in-situ cyclic crack opening and closure behavior of C/SiC composite under loading/unloading tensile was investigated. Experimental matrix cracking evolution and cyclic crack opening displacements (CODs) of short and long matrix cracks were measured using in-situ scanning electron microscope (SEM). Micromechanical cyclic loading/unloading COD models were developed and divided into four cases considering synergistic effects of matrix stochastic cracking and interface debonding. Experimental cyclic CODs of short and long cracks upon unloading and reloading at different tensile peak loads were predicted using the developed micromechanical models. Effects of crack type, fiber volume fraction, and interface properties on cyclic CODs and interface slip ratio were discussed. Relationships between the cyclic CODs, damage state of matrix cracking and interface debonding, and composite constituent properties were established.