Design of Pulsed Magnet for Adjusting the Residual Stress Field in Large-Size Aluminum Alloy Rings

Large-size aluminum alloy rings are widely used as connector, transition ring and reinforcing structure in aerospace and other fields. However, the residual stress introduced during the manufacturing process lead to the structural instability and poor mechanical properties of the aluminum alloy rings. In this paper, pulsed electromagnetic force is used to deform the aluminum alloy rings into plastic state and eliminate the residual stress in the workpieces. The residual stress in a large-size aluminum alloy ring with an outer diameter of 720 mm, a wall thickness of 60 mm, and a height of 60 mm was studied in this paper. To meet the demand of high energy input for bulging the alloy ring, an actuator coil with high voltage insulation and tough inner support was optimized designed by finite element software COMSOL Multiphysics. It was found that adding a steel ring with a truncated gap inside the epoxy skeleton can improve the compression strength of the magnet and increase the plastic deformation of the aluminum alloy ring. Besides, simulation results showed that multiple discharges can reduce the discharge voltage, which can effectively increase the service life and safety of the magnet system.