Magnetic field concentrators or field shapers (FS) are used to improve the efficacy of the electromagnetic forming and joining process by concentrating the magnetic field on the desired workpiece area. The process efficacy and durability of FS depend on its geometrical design. A commonly used circular FS for forming and joining circular or tubular workpieces features a tapered web with a straight slit along its length. However, it often fails in the zone opposite to the slit. The web and slit can be modified geometrically to enhance both their durability and process performance. This study aims to address this problem by proposing alternative designs for the field shaper. The modification in FS design is proposed in the web and slit profile of the FS geometry, and a comparative study of four alternate designs of FS featuring a combination of modifications in web (concave and taper) and slit (curved and straight) is carried out. Finite Element and experimental analysis are carried out and correlated. Results show that the concave FS enhances process performance, achieving 6–8% higher tube deformation and relatively higher velocity, displacement, magnetic field intensity, and Lorentz force. Meanwhile, the curved slit FS effectively reduces induced stresses by 25% to 64% compared to the currently used straight slit FS, thereby improving durability. These findings indicate that the FS with a concave web and a curved slit can significantly enhance process efficacy/performance and durability, contributing valuable advancements to the EMFJ technique.
Gavel et al. (Thu,) studied this question.