Experimental And Numerical Study On Springback Of HSS Sheets V-bending Under Variable Forming Speed And Forming Load

Springback is one of the difficulties in sheet metal forming process, which seriouslydecreases the product geometrical accuracy and brings big trouble to the followingassembly work. Compared to the ordinary carbon steel sheet, springback of high strengthsteel sheet is more and more serious. With development of automobile lightweight, theproportion of high strength steel sheet is increasing more and more high in automobilemanufacture. In order to meet the needs of high strength steel sheets in automobileindustry, it’s necessary to improve the quality of high strength steel sheets forming.Therefore, how to predict and control springback accurately has become one of theresearch focus in the field of high strength steel sheets forming.Firstly, this paper introduces the mechanism of sheet stamping springback andrelevant influence factor. Analytical methods and numerical simulation methods arediscussed, especial the influence of material constitutive model on simulation accuracy ofspringback. In order to increase the prediction accuracy of springback, anisotropy of highstrength steel sheet must be considered and select anisotropy constitutive relation duringspringback simulation. Then, in this paper, the springback behaviours under differentforming speed, forming load, and slider displacement of servo press is investigated byV-bending experiment and simulation methods.The results show that the amount of springback will decrease obviously with theincrease of forming load, punch displacement, and the times of multiple-bending. But, theeffects of forming speed and holding time at the bottom dead center on the springback arevery small. Therefore, the springback of forming high strength steel sheets can becontrolled by controlling the forming load, punch displacement and bending times.