Numerical Simulations to Investigate the Efficiency of Joint Designs for the Electro-Magnetic Welding (EMW) of the Ring-shaft Assembly

In this study, numerical simulations on electro-magnetic welding (EMW) were conducted for dissimilar materials joint of the ring-shaft assembly. LS-DYNA® electromagnetism module was adopted to simulate the EMW process. Simulation results were correlated with the EMW experimental works with two different joint designs, single and double flared lap joint. Two different materials, aluminum 6061-T4 and copper, C40, were used for the driver ring material on the stationary steel shaft. LS-DYNA simulation model was used to investigate the effects of impact angle and velocity on surface-layer bonding and joining efficiency of the driver ring on a steel shaft. Analytical modeling was also conducted to estimate the magnetic pressure between the coil and the ring. Experimentally, a 90-KJ machine was used at different energy levels. From these experiments, the double flared lap joint showed better joint efficiency and the copper showed better adhesion than aluminum at same energy levels. The performance of joint was evaluated by push-off testing. A double flared copper ring at 81-KJ gave the best performance of joint, and exceeded the required axial thrust load requirement. From the metallographic analysis, the interface of joint did not show the metallurgical bonding, however, strong mechanical interlocking was achieved. This study demonstrates the viability of EMW process for dissimilar material joining.