Analysis And Design Of Stamping Process Of Longitudinal Beam Body

In order to improve the safety of automobile and achieve the development needs of Vehicle Body Lightweighting,more and more high strength steel sheets are applied to the body of an automobile.Due to the use of high-strength steel,the number of automotive parts is reduced,the weight of the body is reduced,the fuel efficiency is improved,the life of the automobile is prolonged,and the crashworthiness of the vehicle is improved,so that the purpose of Vehicle Body Lightweighting and environmental protection is achieved.But in the forming process of these structural parts,the problem in the forming process of the longitudinal beam is prominent on account of the complex shape,the high surface height,and the large yield strength of the parts.The main problems are cracking,springback,side wall warping and wrinkling.In these three problems,the springback and side wall warping are more difficult to solve.The dimensional accuracy of the product is badly affected by the two problems,which brings great difficulties to the welding matching of the post process.Springback is a main performance index to determine the forming quality of high-strength parts.In this paper,forming defects such as springback and side wall warping are studied in the case of U-longitudinal beam with high strength plate,which from the structural characteristics,process design and simulation analysis of the part.The specific contents are as follows:(1)The longitudinal beam parts of car body are very important to the safety of the car,and high accuracy is required.Because of its high strength material and complicated structure,it is decided that there will be different quality defects after forming,such as cracking,wrinkling,springback,warping and so on.According to the different causes of all kinds of quality defects,we can eliminate or lighten quality defects of the parts by enlarging product R angle,increasing stiffeners,designing springback compensation and adopting segment drawing technology.(2)According to the structural features of the part described in this paper,the stamping process is formed by four processes.According to the shape of the part,the Die-face of the parts is designed for the smooth and smooth "V".The distance of the drawbead to the opening line is set to 20 millimeters,and the distance of the drawbead to the trim line is set to 12 millimeters.The bending angle of the part is larger,which is about 144 degrees.According to the principle of the trimming angle,the trimming of the longitudinal beam part is completed by two processes.In order to solve the springback,the R angle of the part root is treated side by side in the after procedure.(3)In the stage of forming simulation,the single action draw process is adopted,and the blank holder force is seted to 100 tons.The material is H420LAD+ZF,and the thickness is2 millimeters.For the forming defects in the simulation results,the R angle of the cracking area is magnified,and the two drawbeads are set on the outside of the wrinkling area to increase the feeding resistance.For the springback and side wall warping,on the one hand,we can reduce the degree of bending of the sheet into the die fillet,and reduce the bending deformation,so that the side wall material is easy to be stretched again.On the other hand,we can increase the blank holder force by setting the Locking Bead in the part around before the end of the last 10 millimeters,and increase the tension of the side wall,so as to control the springback and warping degree.According to the above research work,the stamping process design and die tooling development of U-longitudinal beam are carried out.The surface quality and dimensional accuracy meet the quality requirements through the production verification.