Abstract: To reveal the failure rules of adhesively bonded glass fiber reinforced polymer (GFRP)/aluminum alloy and aluminum alloy/aluminum alloy joints subjected to different types of loads and temperatures, adhesive joints under tensile, shear, and combined tensile and shear stress states are manufactured, and tested at -40℃(low temperature), 25℃(room temperature) and 80℃(high temperature) to analyze the effects of temperature and stress state on the failure strength, failure modes and failure criteria of joints with consideration of the glass transition temperature T_g of the adhesive. The results show that the effect of temperature on the failure strength of GFRP/aluminum alloy joint is related to its stress state, but its extent of influence is lower than that on aluminum alloy/aluminum alloy joint. The most failure mode of aluminum alloy/ aluminum alloy joint is cohesive failure in adhesive, while GFRP/aluminum alloy joint is more prone to fiber tear or delamination failure, and hence its goodness of fit of failure criteria drops, with lowering temperature and increasing proportion of tensile stress. Therefore, the proportion of tensile stress should be taken as low as possible in designing the adhesively bonded structure of GFRP for lowering the tendency of fiber tear or delamination, and whose effects have also to be taken into consideration in failure prediction.

Key words: vehicles, GFRP, aluminum alloy, adhesively bonded joints, temperature, stress state, failure