Ultrasonic welding of dissimilar body structures

Modern multi-material vehicles require joining of various lightweight materials such as aluminum, magnesium alloys and advanced high-strength steels together to form a high-performance and lightweight body structure. Conventional fusion based joining methods such as resistance spot welding is challenging due to the difference of material properties. Ultrasonic Spot Welding (USW) as a solid-state joining technique has a unique advantage for joining of dissimilar materials. However, application of USW in body structure joining is difficult due to the structural vibration. In this study, the interfacial vibration and heat generation during the USW process, as well as the resultant microstructures and mechanical performances were studied. In addition, a novel inline control approach was developed to join the component level of the multi-material structures that consist of multiple USW joints and consistent joint quality was achieved.