Electromagnetic tube bulging due to axial pressure produced with a rigid drive block

Three electromagnetic tube bulging methods are studied in this paper as follows: tube bulging without axial pressure (Scheme 1), tube bulging with magnetic axial pressure (Scheme 2), and tube bulging with axial pressure using a rigid drive (Scheme 3). The dynamic deformation characteristics such as displacement, stress, strain, and velocity of the tube were analyzed via numerical simulation and experiments. The deviation of the tube profiles between the simulation and the experiment was less than 7%, which indicates the correctness of the simulation method. For Scheme 2, a small axial magnetic force acts on the tube end because of a thin wall and large coil size. This produces no clear axial compressive strain at the tube end and a reduced bulging height at the tube center compared with Scheme 1. Compared with Scheme 2, the total axial magnetic force increased about 24 times when Scheme 3 was used, which increased both the tube axial feed and the bulging height. Compared with Scheme 1, the maximum diameter (without breaking the tube) increased from 74 to 78.4 mm for Scheme 3.