Boundary controlled automatic remeshing for 2D simulation of metal forming

During finite element simulation of metal forming processes, the mesh undergoes large distortions leading to inaccurate results and numerical instability in the solution process. In order to overcome this problem, the domain is to be remeshed whenever the quality of the mesh or geometrical representation of the contacting boundary violates the desired criteria. This paper describes a strategy, wherein the mesh density during remeshing is controlled by regenerating the boundary segments dynamically, using a background mesh when mesh distorts above allowable limits. This, in conjunction with an advancing front technique is used for generating the finite element mesh. The background mesh specifies the desired length of boundary segments at different locations as per the geometrical configuration of the deforming body and the die. This gives a possibility of remeshing with one background mesh fixed in space and/or multiple background meshes each attached to one of the dies. This also allows easier user intervention if required. The procedure is applied and demonstrated for 2D metal forming problems with quadrilateral mesh generation based on paving technique.