Analyse On Rebound Control For Over Pieces Of Tractors

China is a large agricultural country. The development of agricultural machinery is particularly important. An tractor is an important agricultural machinery. The development of tractor industrial should be paid enough attention to. Panels are important components of the tractors Panels will affect the appearance of tractors. Sheet metal stamping is an important metal processing methods. Sheet metal forming technology, which is widely used in industry field, is an important metal processing way.Wrinkle,split and spring back is the three main defects in the sheet metal forming and springbucks is the most difficult to control.The existence of springbucks will affect the shape, dimensional precision and surface quality of the part. When displacement reaches beyond the permissible error,springbacks will become a processing defect.Springbacks 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 springbucks'problem is both a problem that exists in the industry and a hotspot that the academia has paired attention to for a long time. In order to acquire the local bending spring-back accuracy of sheetmetal strip of a progressive die design, the thesis aims to build ironing depth simulation model in a bending deformation zone. According to the objective condition of wide sheet bending and narrow sheet bending, a series of forming simulation with different relative bending radius at different ironing depth is preformed with the FE code.The aim is to find proper process and to get the least spring-back data.The study of springbucks'in the domestic and abroad mainly focuses on the bend part. The auto panel, which is also focused on the wrinkle and split phenomena, is not so appealing. According to the research of current status, this paper uses the FEM simulation software Dynaform combined with the elastic and plastic FEM to analyze the springbucks rule of the auto panel after drawing and trimming.In this paper, it introduces the key technology of the numerical simulation theory firstly in details based on a great deal of overseas and domestic literature information. It points out that we should adopt elastic and plastic FEM in analyzing the sheet forming. Secondly, in this paper, it analyzes the reason of springback during the process of the sheet forming and introduces the way of the constructing model and computation method in the research of springbacks.And the factors which influences on springbucks is analyzed. In the following, the mechanics and finite element model of S beam is founded and the rule that the element type,the least element size influence on springback is obtained by using the Dynaform software.The rule that the radius of convex-concave mold,the clearance of mold influence on springback is also obtained. Last,it introduces some ways to control the springback.And the simulation results and die surface compensation method are used to control the springback of the typical inner auto panel-front extension to side panel. 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. By the studied,the rule of springback on the s beam is discussed by using the finite element method.And die surface compensation method used to control the springback of front extension to side panel is studied.The research results can guide the production of other similar drawing parts in controlling springback.