Behaviors of GFRP-steel bonded joints under cyclic loading after hygrothermal aging

Abstract This paper presents experimental results of double-lap steel Glass Fiber Reinforced Polymer (GFRP) bonded joints which were subjected to fatigue loading after different harsh environmental aging. Bonded joints were manufactured, cured, and tested to study the fatigue behaviors of the GFRP-steel bonded specimens after hygrothermal aging. Experimental results indicated that the hygrothermal environment could negatively affect the fatigue performance of the bonded specimens. In particular, in comparison with the reference specimens, the most significant reduction of fatigue life for harsh cured specimens was 61.2% when the load level was 70% of the ultimate tensile strength. Finally, based on the analysis of the energy dissipation in each load cycle, relative energy dissipation Ere of each specimen was proposed, by which the accelerating point of Nac was obtained to quantify the damage evolution of the bonding joints under cyclic load after being cured in a certain hygrothermal environment.