Dynamic Analysis of Scarf Adhesive Joints in Carbon-Fiber Composites at Different Temperatures

Abstract

The dynamic performance of scarf adhesive joints (SAJs) in fiber-reinforced polymer composites is a new topic that is not available in the literature yet; introducing it is one of the objectives of this study. Changes in stiffness, ratcheting strain, loss factor (), loss modulus (), storage modulus (), dissipated energy (), and potential energy () with the number of fatigue cycles were measured at room temperature (RT), , and 50°C. It was found that fatigue lives were longer at than at RT and 50°C. Fatigue life at plastic strain threshold was decreased by about 98% of the joint lifetime at 50°C. The behavior of agrees qualitatively with and . The improved ductility of the SAJs at 50°C induces significant changes in and , and hence they can be used to monitor the integrity of the SAJs and early prediction of fatigue failure. At , the and behave approximately in a linear constant manner up to sudden failure without warning. Accordingly, safe design fatigue life based on time to first failure was applied to evaluate the stress versus number of cycles to failure curves of the SAJs at different reliabilities.