The Finite Element Inverse Approach And Optimization Of Process Parameters

The automobile body panel forming technology plays an important role at the sheet forming industry. From the viewpoint of mechanics, it concerns three kinds of non-linear problems, i.e. geometry, material and boundary friction. Therefore, the prediction and analysis of the forming behaviors have to use numerical simulation methods based on computer. But the incremental Finite Elements Method (FEM) requires considerable computation time, especially at the initial stage of panel die design, since many factors are unknown at this stage which leads to redundant iterations. The finite elements Inverse Approach (IA) can solve this problem well. Only considering the initial and final stage of the parts makes IA method fast and high-effective. So it is a good choice to use this method in the initial stage of the die design. The theories and application of IA method were introduced in this thesis in detail. IA method considerates the parameters such as friction, blank hold forces and drawbead precisely. By using the fast–solving arithmetic, this method is more effective, especially for the large punch parts. The IA method is applied to the optimization of important process parameters such as the blank holding force (BHF) and drawbeads restraining forces (DBRF) where the objective function is defined to minimize the error tolerance of thickness distribution on the workpiece. Numerical simulation shows that this method can analyze the deformation of sheet metal forming part qualitatively rapidly, and can be used for the optimization of the process parameters.