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Electromagnetic clinching (EMC) is a high-speed connection technology that combines electromagnetic forming and mechanical clinching. The die structure significantly affects the mechanical properties of the joint. In this paper, an optimal method based on response surface methodology (RSM) and particle swarm optimization algorithm (PSO) is proposed to improve the mechanical properties of joints clinched by EMC. The mathematical models of die geometrical parameters and cross-sectional parameters of the joint are obtained by RSM and numerical simulation. Then, the die structure is optimized through PSO. Finally, the experiments are carried out using the optimized and standardized die. The results show small errors between the simulation and the experiment. The joint strength using a standardized die is 878 N, and energy absorption is 0.758 J. The joint strength using the optimized die is 1322 N, and energy absorption is 1.335 J. Compared with the standardized die, the joint strength and energy absorption of parts obtained by the optimized die are increased by 50.5% and 76.1%, respectively. [ABSTRACT FROM AUTHOR]

To solve the problem that 7075 aluminum alloy tends to fracture during conventional forming processes, a novel forming method (electromagnetic hot forming) is introduced and investigated in this paper. The optimum mesh number (in the thickness direction) is obtained for loose-coupling method and sequential-coupling method. Then, both the loose-coupling method and the sequential-coupling method are compared with the hot forming process, and the dynamic sheet-deformation process is analyzed. With increasing temperature, the sheet forming height decreases before it increases. The simulation results, which are calculated using the sequential-coupling method, are consistent with the experimental results for four different temperatures. However, regardless of the forming temperature, either the sheet profile or the maximum forming height of the loose-coupling method differs significantly from the experimental results. [ABSTRACT FROM AUTHOR]

Electromagnetic forming (EMF) can greatly improve the materials forming limit, but how to improve the energy utilization of EMF is an urgent problem to be solved. In this paper, the method of current assisted electromagnetic forming (CA-EMF) was proposed and compared the deformation process with traditional EMF. Three forming schemes were carried out to analyze the effects of steel die and bridge structure on current distribution and deformation result of sheet metal. The results show that steel die which is commonly used in traditional EMF was not suitable for CA-EMF. Then, the epoxy plate die with good insulation is used to replace steel die, and a bridge structure is used to form a current loop with the sheet during CA-EMF process. Thus, the current density and electromagnetic force in the deformation area of the sheet were significantly increased. Therefore, CA-EMF is an effective means of improving the plastic deformation effect of metals. The sheet-deformed profile and forming height obtained from experiment and simulation were compared, and the correctness of simulation was proved. [ABSTRACT FROM AUTHOR]

High-strength aluminum alloy has been widely used in aerospace and other industries. In the traditional bending process, a large springback occurs for high-strength aluminum alloy sheet due to its higher yield strength and lower elastic modulus. In the past, many scholars found that electromagnetic forming (EMF) can significantly reduce the springback effect. However, the electromagnetic-assisted bending and low-yield-strength aluminum alloy were used in the past researches. If the electromagnetic force is used to bend the high-strength aluminum alloy, what is the different of plastic deformation laws and springback effect both in electromagnetic forming and traditional bending? Those are the research interest of this paper. Thus, we have studied the influence of electromagnetic direct forming, electromagnetic drive forming, and traditional stamping on deformation uniformity and springback of high-strength aluminum alloy sheets. The deformation and stress distribution were analyzed by numerical simulations. The accuracy of the simulation was verified by experimental results. The results reveal that both electromagnetic direct forming and traditional stamping endow a large springback effect. It must also be mentioned that the high-strength aluminum alloy sheet dented on the center after electromagnetic direct forming, which reduces the sheet deformation uniformity. However, a small springback occurs on sheets due to small residual stress and the final deformed sheet has a smooth profile by electromagnetic drive forming. Thus, the electromagnetic drive forming is an effective mean to reduce springback and enhance deformation uniformity for high-strength aluminum alloy sheets. [ABSTRACT FROM AUTHOR]