Research On Multi-step Quick FEM For Sheet Metal Forming

Simulation of sheet metal forming has been widely used in the aerospace, automotive and other manufacturing areas, during the initial design stage, designers usually use one step forming inverse approach to simulate the sheet metal, and quickly evaluate the formability of the sheet metal. In order to ensure the calculation efficiency, and at the same time improve the calculation accuracy, based on the one step forming inverse approach, domestic and foreign scholars put forward intermediate configuration approach to considering the deformation of sheet metal loading history, however, the intermediate configuration solution does not have a complete solution, the structure of intermediate configuration for complex parts is very difficult. in this paper, the middle configuration of the finite element of the multi-step quick forming sheet metal approach has been carried on the study.First, during the process of the intermediate configuration structure, this paper put the method based on the basic ideas of trial and error, and the balance of sliding constraint surface geometry of the intermediate configuration iteration method is studied, using space bounding box and ray method to judge the position relationship between slip constraint nodes below the primary side and die, build the geometric balance configuration under the condition of slip constraint surface.Second, during the surface stress equilibrium iteration process, introduced the method of the tensioned membrane structure architecture for shape analysis, according to the forming process of sheet metal and mold's contact force between the coordination way to adjust the node status, through the direct projection method to obtain approximate solution of the initial solution structure, intermediate configuration based on the linear elastic deformation of initial solution way to solve the middle configuration, on this basis, through the plastic iterative to obtain intermediate configurations.According to the above method, this paper realized configuration of the middle structure based on trial and error method basic ideas, and through the boxes and some automotive covering parts' calculation, contrast DYANFROM incremental methods' result and experimental data, verified the multi-step quick forming sheet metal approach is feasible and practical.