Research On Forming Numerical Simulation Of The Rear Door Hinge Reinforcement Part

Automotive industry plays an important role in our country. The key technologies are part forming and die design. The shape of automotive panel is complex and its size is large, so that in stamping forming process, it is easy to produce defects, just like wrinkle, crack, insufficiently drawing and springback. With the development of modern science and technology, computer technology has gradually applied to every aspect of life. The most widely used technology in automotive part forming is the numerical simulation technology. It can simulate the forming parts before the production by using the technology, design the reasonable stamping process, shorten the production cycle and save costing.In this paper, first the theoretical basis of sheet metal forming numerical simulation technology, including the yield criterion, the constitutive relations and theory of the unit were introduced. Autoform software was used to simulate the forming process of the door hinge reinforcement part, the related instructions about the various defects of the forming part were illustrated, and the forming process was optimized resulting in decreasing the defects. The main research works were as follows:(1) The manufacturability was analyzed, the stamping direction was determined, the process addition was designed, and the finite element was established in the former stage of processing. The effects of material parameters and process parameters on the forming and springback of the door hinge reinforcement were analyzed. The results showed that, the forming force of steel sheet was larger than that of aluminum alloy sheet, but the forming performance was better, when forming the same shapes of stamping parts. Besides, increasing the friction coefficient and the blankholder force and reducing the die clearance were beneficial to decrease springback amount. However, the thickness of the parts was too little, and forming quality was worsen. In this paper, under the situation of good quality, the sheet metal flowing could be effectively controlled, the part wrinkling was prevented, and springback amount was reduced by appropriately increasing the blankholder force.(2) According to the first drawing simulation results, the causes of the forming defects and its solving measures were analyzed. The defects of the part experiencing inadequate deformation, compression, wrinkling were produced by using drawbeads in the forming process. To solve these problems, the appropriate drawbeads were set up around the part. The defects were reduced, but there are some defects still consisting, and the decreasing of the defects appearing area was limited. Therefore, increasing the blankholder force, reducing die clearance, changing the intensity of the drawbeads further improved the forming condition of the part. The forming defects of the rear door hinge reinforcement are basically eliminated, and the scheme is effective and feasible.(3) Simulation was carried on unloading springback and trimming springback of the door hinge reinforcement after drawing process, the reasons of large springback in some area and the decreased springback were analyzed after trimming and punching. The results showed that the forming performance of the part was good, and springback compensation was not needed.(4) According to the results of the simulation, the appropriate stamping process plan was made, then the dies of the rear door hinge reinforcement used in drawing were designed and manufactured. Based on the shape features of the part and the actual production processing, the experiment was carried on and the qualified product was produced by using the optimized scheme. The results showed that the forming defects and springback were effectively predicted and controlled to improve the production efficiency and the forming quality, through the finite element numerical simulation technique.