Code_Aster can project fields at integration points

24 March 2011

by A. Bérard, EDF R&D / AMA

Transferring data from a mesh to another is a frequent task in the field of mechanics : chained studies, remeshing caused by crack propagation for instance or quality measurements of a result are examples that make use of such a process.

The PROJ_CHAMP command has permitted for a long time to transfer data from mesh to mesh, but only on nodes. The mesh transfer on Gauss points is indirectly possible, but requires several interpolations, which can be a tedious work and can generate a lack of numerical precision.

The PhD work of Alexandre Bérard [supervised by Patrick Hild (university of Besançon), Valérie Cano and Sébastien Meunier (EDF R&D) ] deals with the task of direct projection from and to Gauss points, which is a tricky mathematical problem.

The new method ‘ECLA_PG’ in PROJ_CHAMP allows direct projections of the stress fields as well as strains or internal variables. Every field from all results will soon be transferable with a unique call to PROJ_CHAMP.

Last but not least : this new method preserves the boundary properties of the field to be transferred. In practical terms, a field of total plastic strain will never have negative values after projection, which cannot be strictly guaranteed with node-to-node projection.

Elastoplastic computation, with mesh refinement depending on the total plastic strain, and projection of the internal variables and the stresses.