Effect of interface damage on tensile behavior of fiber-reinforced ceramic-matrix composites after thermal fatigue loading

Abstract

ABSTRACT In this paper, the effect of interface damage on the tensile damage and fracture of fiber-reinforced ceramic-matrix composites (CMCs) after thermal fatigue loading is investigated. The damage mechanisms of matrix cracking, fiber/matrix interface debonding and wear, interface and fiber oxidation, and fiber failure after thermal fatigue loading are considered in the tensile stress-strain behavior prediction. The relationships between the thermal fatigue temperature, applied cycle number, composite internal damage, and tensile damage and fracture are established. The effects of thermal fatigue temperature, thermal cycle number, fiber volume, interface shear stress, fiber strength, and fiber Weibull modulus on the tensile damage and fracture of fiber-reinforced CMCs subjected to the thermal fatigue loading are analyzed. The experimental tensile stress-strain curves of different C/SiC composites with and without thermal fatigue loading are predicted. When the thermal fatigue temperature and applied cycle number increase, the composite tensile strength and failure strain decrease, the interface debonding ratio, interface oxidation ratio, and broken fibers fraction increase at low applied stress level.