Analysis and Optimization of the Electrohydraulic Forming Process of Sinusoidal Corrugation Tubes

Aluminum alloy thin-walled structures are widely used in the automotive industry due to their advantages related to light weight and crashworthiness.They can be produced at room temperature by the electrohydraulic forming process.In the present study,the influence of the related parameters on the forming quality of a 6063 aluminum alloy sinusoidal corrugation tube has been assessed.In particular,the orthogonal experimental design(OED)and central composite design(CCD)methods have been used.Through the range analysis and variance analysis of the experimental data,the influence degree of wire diameter(WD)and discharge energy(DE)on the forming quality was determined.Multiple regression analysis was performed using the response surface methodology.A prediction model for the attaching-die state coefficient was established accordingly.The following optimal arrangement of parameters was obtained(WD=0.759 mm,DE=2.926 kJ).The attaching-die state coefficient reached the peak value of 0.001.Better optimized wire diameter and discharge energy for a better attaching-die state could be screened by CCD compared with OED.The response surface method in CCD was more suitable for the design and optimization of the considered process parameters.

Effects of Standoff Distance on Magnetic Pulse Welded Joints Between Aluminum and Steel Elements in Automobile Body

In industrial production,the standoff distance of magnetic pulse welding(MPW)is a critical parameter as it directly affects welding quality.However,the effects of standoff distance on the physical properties of MPW joints have not been investi-gated.Therefore,in this study,aluminum alloy(AA5182)sheets and high-strength low-alloy steel(HC340LA)sheets were welded through MPW at a discharge energy of 20 kJ,under various standoff distances.Thereafter,mechanical tests were performed on the MPW joints,and the results indicate that there is a significant change in the shear strength of the AA5182/HC340LA-welded joints with respect to the standoff distance.When the standoff distance ranges from 0.8 to 1.4 mm,the strength of the joint is higher than that of the base AA5182 sheet.Microscopic observations were conducted to analyze the interfacial morphology,element diffusion behavior,and microdefects on the welding interface of the AA5182/HC340LA joints.The AA5182/HC340LA joint with a standoff distance of 1.4 mm possesses the longest welded region and the largest interfacial wave.This interfacial wave pattern is suitable for achieving MPW joints with high shear strengths.