Interfacial damage behavior of CFRP-steel bonded joints subjected to combined elevated temperature and low-cycle cyclic loading

This study aims at investigating the damage behavior of CFRP-steel bonded joints subjected to the combined temperature elevation and low-cyclic loading. A series of single-shear pull-off tests of CFRP-steel bonded joints was conducted under elevated temperatures and low-cycle cyclic loading. The failure mode, load-displacement curve, bond-slip relation and damage behavior were investigated. Results showed that compared to the bonded joints employing Sikadur-30 presented in existing literatures, the investigated bonded joints using Sikadur-30CN exhibited remarkably higher load-carrying capacity and a significantly brittle failure mode which switched from cohesion failure to the interlaminar failure. The load-carrying capacity is not affected by the elevated temperature when the temperature is below 50℃. However, the failure mode changed to adhesion failure. When the temperature elevated, the deformation distribution curve along the bonding line flattened while the damage parameter, as well as the amplitude of the damage change, increased with the testing temperature.