A review on failure mechanism and mechanical performance improvement of FRP-metal adhesive joints under different temperature-humidity

The mechanical property of FRP (Fiber Reinforced Polymer)-metal adhesive joint is easily affected by the different temperature-humidity. In this paper, the failure mechanism of the joint was explored from the joint components (bonding substrates, adhesive and interfaces) to the integral joint in aging environment. It was found that the main factors affecting the property of joint components are different CTE (coefficient of thermal expansion) of adjacent materials, the metal corrosion and the molecular group/chain state. Meanwhile, the polymer property showed the irregular changes during the aging process, and it was discussed from the positive and negative efforts caused by environment. Besides, the fracture surface was selected to study the failure mechanism of the integral joint, and a mixture of different failure modes called as "mixed failure"was suggested. Finally, based on the failure mechanism and mixed failure mode, the approaches for improving the mechanical performance were summarized and a multi-stage strengthening mechanism was given from multi-component and multi-scale.