Search Results

There exists considerable motivation to reduce vehicle weight through the adoption of lightweight materials while maintaining energy absorption and component integrity under crash conditions. Finite element simulations were performed based on impact tests with straight sections of AlMg3.5Mn aluminum alloy tubes that were hydroformed using a high or low pressure operation. A tube formed with the low pressure operation will experience considerably less strain or work hardening and will retain greater residual ductility compared to a tube formed under high pressure, with a trade-off being that the tube will have a smaller cross-section. In the high pressure process, tubes will likely experience more work hardening in the corner-fill region. The energy-absorption behaviour during impact can be affected by the work hardening, residual stresses, thickness changes, and shape of the cross-section after the hydroforming operation.

One of the main challenges associated with the use of aluminum alloys in the automotive industry is increasing their limited formability. Electromagnetic forming has been considered recently as a way of addressing this issue. Increases in formability for several commercial aluminum alloys have been reported in electromagnetic (EM) and other high speed forming processes. These increases are typically attributed to high strain rate and inertial effects; however, these effects alone cannot account for the increases in formability observed. The present authors have previously reported that the increased formability is likely due to damage suppression caused by the tool/sheet interaction. This paper presents an analysis of this interaction and how it affects the formability of the sheet. Experimental and numerical work was carried out to determine the details of the forming process and its effects on formability, damage evolution and failure.