Automated modeling and remeshing in metal forming simulation.

摘要

Process modeling has become an effective tool in reducing the lead-time and the cost for designing forming processes. Process simulation can give comprehensive details including material flow, strain/stress/temperature distributions that assist the designer in honing the process design to obtain optimal results. Commercial finite element solvers to model forming processes such as forging, extrusion, etc. are available. However, a major deterrent in their effective use has been the need to provide a new mesh to represent the deformed workpiece. Until recently, this process, known as remeshing, was performed manually by process designers. Each workpiece remesh can potentially take several days for a complex 3-D component. Hence, an automated modeling environment that would automatically remesh the deformed workpiece when required and continue the analysis can dramatically reduce the overall modeling time and result in this technology being used in the design of industrial forming processes. This has provided the motivation for the thesis research that has led to the development of an automated modeling system for forming simulation. The research effort has focused on the issues that must be addressed in developing an automated modeling system that is robust, has automated procedures to update the geometry and remeshes the deformed workpiece model with concern for controlling the simulation errors.; Major contributions arising out of this work include procedures for (i) automatic remeshing of the deformed workpiece, (ii) use of CAD model of the die geometry during analysis and remeshing, and, (iii) curvature compensation of nodes on workpiece free surface. Curvature compensation of nodes allows us to mimic the smooth geometry on the workpiece free surface. The CAD models enable use of the true geometric representation of the die rather than its of workpiece volume. These procedures have been integrated with the commercial analysis and CAD tools to provide an automated modeling environment. The system has been very successful in modeling forming processes involving complex 3-D geometries, eliminated the need for manual remeshing and reduced the overall simulation time by more than 90%.