Forming Optimization And Springback Prediction Of Automobile Rear Door Outer Panel

Due to the complex curved surface and thin material,automobile covering parts have some typical defects after forming.Moreover,with the improvement of the quality of life,people have higher pursuit of exterior parts,like car door outer panel,which requires the advantage of good utility properties and beautiful aesthetic shape.This thesis aims at the practical application of a certain type of automobile rear door outer panel of a certain company,and mainly makes the following research:(1)According to the performance requirements that the car rear door outer panel,by the process of analyzing the characteristics of the material B180H1,making sure the forming process and the best stamping angle,explaining the design principles of the blanking surface and the process supplement surface and making the schematic diagrams of each process,we get the main process parameters and their range values and establish the finite element model.(2)A 4-factor,4-level Taguchi test was designed for the four main parameters affecting the effect of drawing without considering the resistance of the drawbead.The simulated results were compared and analyzed to derive the best combination of parameters for the simulation.Then the Taguchi design was analyzed,and the four parameters were computationally searched for the minimum and maximum thicknesses as indicators,and two computationally optimal combinations were derived.Then the sheet forming quality of these 3 combinations are compared to arrive at the optimal solution,i.e.,800 k N of blank holder force,0.88 mm of die clearance,0.14 of friction coefficient,and 3000 mm/s of stamping speed.Finally,based on the optimal parameters,a 4-section drawbead that can achieve the best forming effect is simulated with 45%,50%,40%,and 50% of resistance coefficients,respectively.(3)To address the issue of the accuracy of rebound prediction,this thesis takes the first step on the hat-shaped part as an example and conducts 6 sets of tests for 3 different constitutive models and 2 different measurement methods for the B180H1 material,respectively.The tests show that the 125# material model has higher accuracy;in the case of the 125# material model,the results using the inertial release method and the nodal restraint method are both close to the measured values,and their average rebound relative errors are 18.1 % and 21.4 %,respectively.Then the two combinations were applied to the rebound simulation of the automobile rear door outer panel,and the differences between the average values of the relative errors of the two simulated values and the actual rebound values are 3.0 % and 3.7 %,which illustrate the reliability of the simulation.(4)The forming simulation was carried out for the shaping and flanging processes;two different rebound calculation steps and rebound compensation methods were illustrated to predict the rebound amount of each process of the workpiece;and the inspection of the surface and contour of the part with the help of the process hole was carried out by using the inspection tool to meet the requirements of use,and the reliability of the simulation was verified.