Adaptive remeshing and error control for forming processes
Keywords:
error estimator, adaptive meshing, remeshing, Delaunay tessellation, viscoplasiicity, non steady-state process, metal forming, forging, machiningAbstract
In order to take into account the large deformations of the material, the numerical simulation of forming problems invokes a great number of meshings. For effective treatment of meshing and remeshing, error estimators have been considered as a guiding tool. The present work especially concerns methods for the construction of adapted meshes when an optimal size criterion has been calculated from error estimators. The remeshing procedure is based on the Delaunay type mesh generator and on the uncoupling between geometric and adaptivity constraints of the remeshing problem. The procedure is tested for various elasticity and viscoplasticity problems. It is shown to be robust and reliable, then it is used to compare the efficiency of two error indicators which stem from the Z2 (Zienkiewicz and Zhu) error estimator and the .6. error estimators (a correction of the Z2 estimate in order to take into account the unbalancing of the smoothed stress tensor) which have been suggested in a previous paper. Singular problems are tackled: iterations of the adaptive remeshing method makes it possible to solve them. This method is then used to control the discretization error during several non-steady complex forming problems.
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