Analysis And Control Of Springback For The Pillar Of Bumper Based On FEM

Sheet metal forming technology, which is widely used in industry field, is an important metal processing way. Wrinkle, split and springback is the three main defects in the sheet metal forming and springback is the most difficult to control. The existence of springback will affect the shape, dimensional precision and surface quality of the part. When displacement reaches beyond the permissible error, springback will become a processing defect. Springback problem becomes more impressing, especially with the use of the high strength sheet steel and the aluminum alloy steel in the automobile body manufacturing. So springback problem is both a problem that exists in the industry and a hotspot that the academia has paid attention to for a long time.The pillar of bumper is an important structure, which is welded with corrugated sheet and base, bearing the great collision impact. So it plays an important role in safety area. The part is mainly deformed by the way of bend and it will cause springback after forming. And the existence of springback will affect dimensional precision and the following process of welding and assembly. So, the study will focus on the predicting of springback and controlling of springback by using optimized parameters of processing and structure of mold.In the past, the designers will predict the springback of part after forming by their own experience. It is subjective. But, the numerical simulation is becoming both a tool and a key technology, which can change tradition process of plastic forming and improve design ability of mold, with the development of technology of plastic forming for metal. The flowing of metal can be analyzed and the defects such as wrinkle, split and springback can be predicted by using the technology. Then the optimized scheme and parameters based on the analyzed results will be used to reduce or eliminate the defects. And these processes can guarantee quality of part and shorten the period of design.In this paper, the forming process of the pillar of bumper has been studied by using the FEM simulation software Dynaform, according to the elementary theory and method of elastic and plastic FEM. Firstly, in the paper, the reason of springback during the process of the sheet forming is analyzed and the way of the constructing model and computation method in the research of springback is introduced. At the same time, the effect of factors on springback is analyzed. Then, the characteristic of process for the pillar of bumper is analyzed in details. And the reasonable scheme of process is determined by compared with the possible scheme of process. The undetermined factors will be determined by using numerical simulation. Finally, the optimized scheme of process will be used to guide the production. By using the numerical technology, changes of a variety of field variable are analyzed and the flowing trend is predicted. At the same time, the rule that the gap of tools, the friction coefficient and the fillet of punch influence on springback of the pillar of bumper is obtained and the optimized parameters are determined. The influence of parameters of simulation such as virtual punch velocity, the number of element at fillet of mold on springback is studied. Finally, it introduces some ways to control the springback. And the optimized process parameters and die surface compensation method are used to control the springback of the pillar of bumper. And the rule of springback and the control method is proved by test. Then it obtains a good result in controlling the springback of other parts by using the research conclusion of the pillar of bumper.By the studied, the rule of springback on the pillar of bumper is discussed by using the finite element method. And die surface compensation method used to control the springback of the pillar of bumper is studied. Finally, the molds are designed and the eligible part is obtained.