Study on the fracture failure criteria for bonded structures considering temperature sensitivity

The fracture failure of a bonded structure is closely related to the service temperature. In this study, based on the failure criterion of an adhesive structure at room temperature and considering the influence of temperature sensitivity on an adhesive structure, ISR-7008/aluminum alloy adhesive joints in the vehicle service temperature range (−40–80 °C) were taken as examples to establish the full service temperature range fracture failure criterion based on the equivalent stress. Adhesive dumbbell-type specimens were made, and adhesive joints with angles of 0°, 30°, 45°, 60° and 90° were designed. The tensile test was conducted at seven typical temperature points in the service temperature range: −40 °C, −20 °C, 0 °C, 25 °C, 40 °C, 60 °C and 80 °C. By analyzing the stress state of the failure position and failure point of the bonded structure, it was found that the equivalent stress σeq composed of the stress component J3*J2* can satisfy all of the conditions and can be used as the failure criterion for the adhesive joint. The application results of the failure criterion show that the maximum relative error of the test and simulation results is 17.36%, the average relative error is 10.75%, and the related precision meets the requirements of engineering applications.