TENSILE FRACTURE OF FIBER-REINFORCED COMPOSITES - INFLUENCE OF THERMAL RESIDUAL EFFECT

The inclusion model is used to analyze the tensile fracture of fiber-reinforced brittle-matrix composites containing many unidirectionally aligned continuous fibers with uniform strength. During the debonding of fiber-matrix interfaces, the fibers slide against the friction which is caused by Poisson's effect and thermal expansion mismatch. In general, three fracture mechanisms including interfacial debonding, matrix cracking and fiber failure may occur in some sequence. The sequences are strongly influenced by the thermal residual effect due to the temperature change DELTAT. The analysis provides an explicit crack length/applied stress relationship for each mechanism. Fracture maps are constructed to analyze the influence of thermal residual effects on the fracture sequences and final composite strength. Two categories of fracture transitions are defined analytically for the large-crack limit.