Effect of interference fit size on tensile strength and fatigue life of CFRP/Ti alloy bolt joints

Abstract

An experimental investigation is conducted to determine the effect of interference-fit size on tensile strength and fatigue of CFRP (carbon fiber-reinforced plastic)/Ti alloy bolted joining structure. The tensile test and fatigue experiments of interference-fit specimens are performed. The joints with four interferences-fit sizes (0%, 0.8%, 1.7% and 3.4%) are tested. The loading-displacement curves and fatigue life data of CFRP/Ti alloy bolted joints with various interference-fit sizes are obtained, and the relationship between interference-fit sizes and fatigue life are presented. The results show that the fatigue life of CFRP/Ti alloy bolted joint are associated with the size of interference fit and the dynamic stress levels, and the appropriate interference fit can improve fatigue life of CFRP/Ti alloy bolted joints compared with non-interference fit. Excessive interference fit can decrease the initial stiffness, ultimate bearing strength and fatigue life. In this paper, the joints with 1.7% interference fit have the best bearing and fatigue performances. Besides, fatigue empirical formula and fatigue damage of mechanism have been presented.