Based On Research The Car Lampshade Parts Drawbeads, Contrast,

Drawbead is critical in the sheet metal forming, expecially for those large and complex stamping part. But up to now, it is still difficult to accurately simulate the sheet forming behavior when the sheet passed drawbead. When simulated the process of sheet passing drawbead,drawbead must be divided into many small finite element mesh in order to exactly express the drawbead's geometry dimension and figure, in comcerning the contact of sheet and drawbead. This caculating method influences not only the efficiency, but also the difficulty of numerical calculation. So equivalent dawbead model is applied to simulate three-dimesion sheet forming numerical simulation. But equivalent drawbead model can not exactly reflect sheet forming behavior as the sheet passing the real drawbead. So there is a deviation between simulation and real stamp. This paper applys the finite element numerical simulation and experiments to study of above problems based on the former research. The content includes:1.Systematic study of numerical simulation theory and key techology of sheet metal forming. From the basic properties of sheet metal forming, the numerical simulation theory and key technology are discussed,such as sheet metal forming numerical simulation method, the non-linear problems of sheet forming numerical simulation, including geometry, matarial and boundary condition; the geometric description of die cavity surface; the technology of finite element mesh re-compartmentalized;arithmetic selection and the forming limit judgement rule, and so on. The numerical simulation software of sheet metal forming is introduced, and the problems of numerical simulation and the development trends are pointed out.2.The car lamp part is taken as an example to estsblish equivalent drawbead model and real drawbead model. Through numerical simulation, the influence of BHF and virtual veloicity for sheet metal forming state when it passed drawbead is analyzed. The relation of sheet metal passed equivalent drawbead and real drawbead is compared. At last the real drawbead model considering the drawbead end shape is studied. 3.The sheet metal forming behavior passing drawbead is tested with the TE Drawbead-friction tester. The hardening phenomenon of sheet metal is serious and drawbead resisting force increase obviously when passed drawbead. BHF has obvious influence for sheet metal thinning after it passed drawbead. With BHF increased,sheet metal thinning exits a break value.It is coincident with real drawbead model simulation result, and it indicates that the simulation result with real drawbead model is authentic and credible. With BHF increased, the drawbead resisting force is increasing. And there is a linear relation between them. The influence of virtual veloicity for sheet metal thinning is not obvious.4.The optimization design of car lamp part is done. Firstly, the blank shape of car lamp part is optimized, and the reasonable blank shape is obtained;Secondly, the forming technics parameter is optimized, such as material property parameter(n value and r value), BHF and friction coefficientμ. At last, the drawbead layout method on the die is optimized, making car lamp part forming process well-off.