Effect of hygrothermal environment on the fatigue fracture mechanism of single lap Aluminum-CFRP hybrid (riveted/bonded) joints

• Hybrid(riveted/bonded) joints’ fatigue failure has multi-stage character. • Dissimilar failure sequence under different hygrothermal environments and load conditions. • Complex failure behavior attributed to fatigue competition mechanism. • 12 possible fatigue failure modes of hybrid(riveted/bonded) joints are summarized. Due to being composed of different materials, Aluminum-CFRP hybrid (riveted/bonded) joints (HJs) exhibit different fatigue failure modes under different loading and environmental conditions. This paper investigates the influence of hygrothermal environment on the fatigue fracture mechanism of HJs through experimental and simulation researches. Experiments demonstrate the multi-stage character of HJs’ fatigue failure with dissimilar failure sequence behavior under different hygrothermal environments and fatigue load conditions. Particularly, through numerical analysis, the competitive mechanism of HJs’ fatigue failure behavior has been first revealed to explain the possible fracture modes of the HJs under different fatigue loading and aging conditions.