Effect of test temperature on the shear and fatigue strengths of epoxy adhesive joints

Double lap joints were prepared using epoxy adhesive and aluminum plates, and their high-temperature strength properties were studied. Tensile, thermal aging, creep, and cyclic fatigue tests were performed to systematically investigate the effects of the aging temperature, testing temperature, stress waveform, and stress ratio on the strength and fracture morphology of the double lap joints. When the specimen was exposed to 135 degrees C, the strength decreased significantly. Also, the relationship between the test temperature and shear strength could be expressed using an equation obtained from thermal activation theory. Additionally, in the fatigue test at room temperature, the strength of the specimen subjected to constant stress was higher than that of the specimen subjected to cyclic strain. The effect of creep deformation increased in the creep test at high temperatures, and therefore, the strength decreased significantly.