Research On Die Design Method And Formability Of Automobile TRB Component

Tailor Rolled Blank,TRB,is manufactured by changing the roll clearance during rolling,Thickness's distribution of the component made with it can be designed by the load cases,which can maximize material utilization and achieve lightweight structure.Compared with the Tailor Welded Blank,TWB,TRB is not requiring laser welding process,hence,it's material properties varies continuously and it has superior surface quality,the application prospect of TRB is considerable in the field of body design and manufacture.Because TRB's thickness varies continuously in rolling direction,it's material properties also varies,which make it's formability difference with common thickness steel blank.In this paper,comprehensive research about the method to evaluate the formability and designing the die of TRB front longitudinal beam was conducted:Test forming limit curves by the Digital Image Correlation method and then build a three dimensional forming limit surface,3D-FLS,in which the Abscissa is minor strain,Ordinate is thickness and Vertical coordinate is major strain.On the foundation of the 3D-FLS,the method to calculate the forming margin,build the forming margin graph and the application of the forming margin graph ware proposed,.Finally,the accuracy of the 3D-FLS was verified by comparing the result of the TRB bulging experiment and simulationTest TRB's constant thickness section's strain-stress curves through uniaxial tensile test,obtain the stress and strain curve of variable thickness zone using lagrange polynomial interpolation,and then anisotropy coefficient is tested using DIC technique.the TRB's variable material properties was simulated by defining material properties according to element's thickness and blank's variable thickness is simulaterd throught seting up the thickness of the node according to the node's position in the rolling direction.According to the characteristics of the variable thickness of TRB,the method to design variable clearance die surface was proposed.Because the large ratio of the length and the width,the blank is not easy to flow in the two end but easy to flow in the middle during stamping.The drawbead was designed in the middle position of the part and the height of drawbead was designed according to the distribution of the thickness of TRB.Stamping simulation of TRB front longitudinal beam was conducted at different process parameter and die structure parameter,An appropriate die surface was designed,The simulation also provides the guidance for the stamping experiment.The accuracy of the finite element simulation results is verified by comparing the simulation results with the experimental results.