The effect of fatigue loading on bond strength of CFRP bonded steel plate joints

This paper describes a series of tests on CFRP (Carbon Fibre Reinforced Polymer) bonded steel plate joints subjected to fatigue loading. The aim is to study the effect of fatigue loading on the bond strength, bond slip and failure modes. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used. The test results were compared with those subjected to static tension alone. It was found that when the maximum applied load is less than 40% of the ultimate static strength there is no fatigue failure in the specimens. When the maximum applied load is less than about 35% of the ultimate static strength, the influence on the bond strength is not significant (less than 10%). A reduction in bond slip stiffness was observed due to accumulated damage caused by the fatigue loading. The failure modes were not affected much by the fatigue loading except for those bonded with high modulus CFRP, where fibre fracture extended over more than one cross-section