Heterogeneous deformation during electromagnetic ring expansion test

Yang, Kang Chernikov, Dmitrii Sapanathan, Thaneshan [UCL] Raoelison, Rija Nirina Gluschenkov, Vladimir Buiron, Nicolas Rachik, Mohamed et al.[show all]

High speed forming methods become attractive in manufacturing and it significantly reduces the cost and energy requirements. Conventional manufacturing processes such as forging, forming, stamping and cutting of metals typically involve a strain rate of 102 - 104 s-1 which includes high energy rate fabrication (HERF) methods [1]. During advanced manufacturing methods such as high speed forming and high speed welding processes, certain local regions (e.g. interfaces) of materials could also experience significantly high strain rate (> 104 s-1). In order to understand the physical behaviours of materials and to design/control/optimise, such manufacturing processes that require an appropriate technique to capture the material's viscoplastic property under the high strain rate deformation. Therein, the electromagnetic ring expansion test becomes a promising method to characterize the material behaviours under the high strain rate deformation. The ring expansion is caused by Lorentz force that is generated due to the magnetic induction on the ring. However, the realistic nature of the electromagnetic ring expansion test is quite complex because of the coupling physics between electromagnetic-thermal-mechanical components. Therefore, in this study we evaluate certain controlling parameters which govern the fundamental behaviour of the electromagnetic ring expansion test. Particularly the rotation and inhomogeneous deformation of the ring are noticeably observed and these phenomena require extra attention. © 2017 International Center for Numerical Methods in Engineering. All rights reserved.