Strength of Tubular Joints Made by Electromagnetic Compression at Quasistatic and Cyclic Loading

Abstract

Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for lightweight structures. The components are joined using pulsed magnetic fields which apply radial pressures of up to 200 MPa to tubular workpieces, causing a symmetric reduction of the diameter with typical strain rates of up to 10^4 sec^(-1). This process avoids any surface damage of the workpiece because there is no contact between component and forming tool. The strength of electromagnetically formed joints made of aluminum tubes under cyclic loads is essential to establish electromagnetic forming in automotive structures. In the present paper, the quasi-static performance of tubular joints made by electromagnetic compression produced of different mandrel materials will be analyzed as to the influence of process parameters. Therefore, experimental investigations on aluminum tubes (AA6060) joined on mandrels made of different aluminum, copper, and steel alloys were carried out. Furthermore, the behavior of joints with both mandrel and tube made of AA6060 at swelling cyclic loads (R = δ_ min / δ_ max =0) has been evaluated.