A METAL-FORMING APPROACH TO AUTOMATIC-GENERATION OF GRADED INITIAL QUADRILATERAL FINITE-ELEMENT MESHES

This paper presents an algorithm for automatic generation of graded in itial quadrilateral meshes targeted for the finite element analysis of metal-forming processes. Meshing the domain geometry deals with a uni verse of shapes, and the procedure therefore takes into account the in itial geometry of the billet. A grid-based approach is utilised for ge nerating an initial coarse mesh with well-shaped (internal) elements, and in cases where non-rectangular shapes are to be discretized, linki ng with the boundary is performed on the basis of constrained Delaunay triangulation. By analysing the contact situation between dies and me sh, an attempt is made to identify regions where plastic deformation i s likely to be concentrated during the early stages of processing, and accordingly refinement of the mesh is performed locally by elemental subdivision. Simulation examples for closed-die forging, forward rod a nd backward can extrusion substantiate the feasibility of this approac h in terms of lowering the overall calculation error and limiting the interference between mesh and die.