Research And Development Of Automotive Panel Stamping Forming Computer Simulation-specific Pre-treatment System

The successful application of computer simulation techniques in sheet metal forming rises a urgent requirement for fully automatic mesh generation algorithm. Unfortunately, most existing mesh generation algorithms are based on the CAD model of tool surfaces and can not really realize full automatization of mesh generation because missing and distortion of geometric information often occur when preprocessing systems for mesh generation receive CAD models from other CAD system.This paper aims at providing some new and less-time consuming methods for engineers with little knowledge of mesh generation to build finite element model for computer simulation of sheet metal forming. An original mesh generation method based on the NC track points of tool surfaces is proposed here, the method can automatically generate meshes consisting of only quadrilateral elements, which is desirable for better accuracy and efficiency of simulation. Besides, an automatic local coarsening algorithm for structured quadrilateral meshes is also developed. For arbitrary discrete points on auto body surfaces, an automatic triangulation method is adopted and a series of mesh optimization methods with given constraint conditions are proposed. An automatic local refining of blank elements based on the curvature of tool surfaces is also discussed here. Based on the above algorithm, a preprocessing software system special for computer simulation of sheet metal forming processes has been developed.For giving CAD model of tool surfaces, the algorithm provided in this paper can fully automatically generate quadrilateral finite element meshes from NC track points of tool surfaces, which include the punch, the blank holder, the blank and the die. In comparison with the algorithm based on the CAD model, the proposed algorithms demands little time on the preparation of CAD model suitable for mesh generation, which reduces the work intension of engineers and makes the building of good finite element model for computer simulation more efficient. Numerous numerical results demonstrate that the finite element models generated by thesealgorithms are little-time consuming and valid.