In the finite element analysis of metal forming processes using general Lagrangian formulation, element nodes in the mesh move and elements are distorted as the material is deformed. Since metal forming processes usually involve large deformation of the material, the severe distortion of elements in the region of concentrated deformation is frequently observed. The excessive degeneracy of mesh interrupts finite element analysis and thus increases the error of plastic deformation energy. The degenerated mesh should be replaced by a new mesh which is known as a remeshing procedure. The remeshing procedure allows one to construct a new mesh with well-shaped elements and transfers the analyzed data from the degenerated old mesh to the reconstructed new mesh.
In this study, a remeshing scheme using so-called mesh compression method is proposed to effectively analyze the flash which is generated usually in hot forging processes. When the working material is deformed to the extent that a thin flash is formed, the mesh compression method is required. The remeshing procedure using the mesh compression method consists of the following four stages : i) Make a surface patch from the degenerated mesh, ii) Expand the surface patch based on the flash, iii) Construct the new mesh in the expanded surface patch using the master grid approach, iv) Compress the mesh to the original shape.
In order to verify the effectiveness of the method, several examples are tested in two-dimensional and three-dimensional problems. In order to show the validity and effectiveness of the proposed scheme, hot forging processes are simulated using the proposed scheme.
From the comparison with the result using the fine mesh in the whole region, it is shown that the proposed method could be effectively applied to analyze the flash deformation in hot forging processes.
