| This study has been carried out to quantify the effect of temperature on impact properties of resistance spot-welded advanced high strength steels 'AHSS' consistent with the Auto/Steel Partnership "AS/P" 'Roadmap' for future application of AHSS. Weld schedules used were the optimized weld schedules previously developed in support of an A/SP project, the Lightweight Front End Structure (LWFES). The experiment was conducted in a temperature range of low (∼ -60°C) to high (∼ +55°C). The impact speed has been chosen at two different levels, 5 and 15mph, to evaluate the joint performance of resistance spot-welded AHSS and mild steel materials. The results of this study will enable for optimal design of automotive structures using AHSS.; Chapter I introduces the Resistance Spot Welding 'RSW' method, the importance of impact testing of the resistance spot-welds in automotive industries, and a brief State-of-the-Art review of current practice.; Chapter II discusses in detail the impact testing method and the instrumentation used including the mechanical and electrical components to acquire the test data.; Chapter III presents the impact test results at two impact speeds of 5 and 15mph. In this chapter statistical analysis method has been employed to present the impact energy data of different material combinations. Expulsion and fracture modes of the resistance spot welds have also been discussed.; It is concluded that the factors such as impact speed, weld quality, material combination, temperature of testing, and a strong interaction between temperature and material combination has significant effect on the performance of the resistance spot welds. |
