Study On Springback And Fracture Behavior Of Electromagnetically Driven 5052 Aluminum Alloy Sheet

As one of the ideal materials in lightweight manufacturing,5052 aluminum alloy is widely used in the design and production of automobile body structures,while traditional stamping technology is prone to problems such as large springback and cracking of parts.Electromagnetic forming is a method of high-speed forming of metal workpieces using pulsed magnetic field force,which can significantly increase the forming limit of the material and reduce the springback of the part.However,the existing electromagnetic forming technology has problems such as complex coil structure and low life of the punch,and it is difficult to precisely control the shape and size of the parts.This paper takes 5052 aluminum alloy as the research object,and uses the combination of experiment and finite element simulation to study the influence of electromagnetic direct drive and electromagnetic auxiliary drive stamping on the springback,deformation,fracture and forming limit of aluminum alloy.Based on the electromagnetic assisted stamping technology,a method of controlling springback by reverse direct drive of electromagnetic force was proposed,and the influence of reverse electromagnetic force on springback control was studied.Using ANSYS and ABAQUS simulation software,the finite element model of 5052 aluminum alloy sheet under electromagnetic force reverse loading was established,and the finite element simulation of sheet metal deformation and springback behavior under the action of quasi-static stamping and dynamic electromagnetic pulse forming was carried out.The simulation results and the experiments results were in good agreement.With the increase of discharge voltage,the amplitude of plate vibration increases,the elastic strain energy decreases,and the springback angle decreases.After electromagnetic correction,the profile deformation of sheet bending area is less than 0.14 mm.Compared with the sheet being flattened to the coil surface,the springback reduction of the stamped sheet to the surface just contacting the coil is greater,and the springback angle of the 6k V formed specimen at these two stamping depths is reduced by 4.6° and 14.9°,respectively.The springback angle of the 7k V forming sample is the smallest,but the side is bent.Aiming at the problem that it is difficult to control the precision of parts in electromagnetic forming,and the forming limit of sheet metal in traditional stamping is low,a new technology of electromagnetic-assisted driving of stamping is proposed,which drives punches by electromagnetic force to carry out high-speed stamping of sheet metal.The quasi-static stamping and electromagnetic assisted stamping were carried out with punches with different fillet radius.The finite element simulation was carried out with GTN damage model to study the springback,forming and fracture behavior of V-bending under quasi-static and high-speed stamping.Compared with quasi-static stamping,high-speed stamping increases the forming height of the part,but has no significant effect on reducing sheet springback.When the punch fillet radius is 15 mm,the sheet material breaks flat under the quasi-static punching method,while the sheet material breaks at 45°under high-speed punching.The deep drawing and fracture behavior of electromagnetically assisted high-speed stamping were studied.Compared with quasi-static stamping,high-speed stamping increases the part forming height by11.4%.Under quasi-static stamping,a large residual stress is generated inside the sheet,and the volume fraction of holes is 0.0379.The residual stress was reduced under the electromagnetic-assisted driving of high-speed stamping,and the void volume fraction was 0.028.And the number of dimples increased and the distribution was more uniform.