Research On Numerical Simulation Accuracy Of Springback And Springback Compensation Of Advanced High Strength Steel Automobile Cover Parts

In recent years, as the development of automobile body lightweight, high strength steel is widely used in automobile to improve its safety and get the target of lightweight. In the forming process, the plastic deformation of high strength steel plate is incomplete because of high yield limit, which leads to the springback of the parts after forming being outstanding. At present, the springback of sheet metal is the most serious problem when the high strength steel is being stampinged. Domestic and foreign researchers pay great efforts to study the problem of springback. The Research methods including test, numerical simulation and theoretical analysis, etc. Now the numerical simulation technology can accurately predict both the fracture and wrinkling of the sheet metal forming, but the prediction accuracy of springback is not satisfying. If the prediction accuracy of springback increases, the accuracy of numerical simulation will increase accordingly.In order to improve the accuracy of numerical simulation, the material model, material element and solving process, the algorithm and contact friction treatment of numerical simulation which affect the precision of springback is analyzed. By comparing the real springback angle(θ1) of U-shaped part and the springback angle of U-shaped part after numerical simulation, Two viewpoints is obtained:first, the more Integral points, the more accurate the precision will be. Second, with the decrease of the cell size, the simulation accuracy will increase. Through the type surface after springback of U-shaped part, mold type surface and the real U-shaped part after stamping, the simulation error function is set up. Dynaform can be used to compensate the springback of the U-shaped part. An appropriate compensation factor being found by combining with the simulation error function will make the U-shaped part which is got from the die after compensated be similar with the U-shaped part which is wanted. Doing so can simulation error be reduced.The back beam is analyzed with Numerical simulation method by adjusting the process parameters which can improve the forming quality, using the optimized points and unit size which can minimize the springback simulation error and use the optimized compensation factor to the mold for compensation. The back beam got from the actual production process is the same as the standard part. By using both the simulation error function and compensation factor can the numerical simulation accuracy be effectively controled.