To perform a similar ring-gear forging simulation using rezoning, consider the following hints and recommendations:
Use rezoning only in problems experiencing mesh distortion as a result of large deformation.
Select the substep to initiate rezoning carefully.
Determine the optimal substep after carefully examining the element solution, the deformed mesh (in /POST1, and the convergence pattern.
The best substep to rezone is the one where the mesh is distorted (though not too severely distorted) and the time increment is not close to (or at) its minimum.
Use an earlier substep or a better mesh if necessary.
If any of the following situations are encountered, initiate rezoning at an earlier substep or improve the quality of the new mesh:
Three methods exist for obtaining a new mesh.
A new mesh can be program-generated (AREMESH and AMESH), created via mesh splitting (REMESH,SPLIT), or read in (REMESH,READ).
If an external mesh (.cdb file) created by a third-party meshing application is used, two considerations exist:
-- If a partial region is rezoned, the nodal locations on the interior boundaries must be retained by the third-party meshing application when creating the new mesh. The locations are necessary to maintain nodal compatibility between the new and existing meshes. -- If PLANE183 (quadratic) elements are used in the original mesh, the third-party meshing software should retain the location of midside nodes by generating the new nodes using element-based quadratic interpolation. More than one region can be remeshed at the same time.
Multiple regions can be remeshed at the same substep via horizontal rezoning. Multiple regions where the new mesh is read in (REMESH,READ) cannot intersect, though they may touch at a boundary.
Repeated rezonings can be performed at different locations in time via vertical rezoning. The only vertical rezoning restriction is that a program-generated mesh (AREMESH and AMESH) cannot be used after obtaining a new mesh either by reading it in (REMESH,READ) or by splitting the mesh (REMESH,SPLIT). (The restriction is due to the loss of associativity of the mesh and geometry which occurs in cases where the new mesh is read in or created from mesh splitting.)
Mesh size affects mapping.
If the new mesh size is drastically different from that of the old mesh, convergence issues may occur during mapping. It may be necessary to resize the new mesh to more closely match the old one.
Specify more substeps if needed.
A larger maximum number of substeps may need to be specified to handle convergence difficulties during mapping and in the restarted analysis.