4. Implementation in Code_Aster and current limits of use#

4.1. Implementation in Code_Aster#

The two previous estimators are implemented in*Code_Aster* in the post-processing command CALC_ERREUR [U4.81.04]. They are activated from options (ERZ1_ELEM for ZZ1 and ERz2_ELEM for ZZ2) and enrich a RESULTAT data structure.

In addition, the calculation of the stress field smoothed by one or other of the methods described in [paragraphe 3] can be triggered separately from the error estimation calculation (option SIZ1_NOEU for ZZ1 and SIZ2_NOEU for ZZ2).

The error estimator provides:

  • one field per element with 3 components:

  • the estimate of the relative error on the element,

  • the estimate of the absolute error on the element,

  • the norm of the energy of the solution calculated \({\sigma }_{h}\).

  • listing outputs containing the same information at the global level (throughout the structure)

All the fields obtained can be viewed using the IMPR_RESU command.

4.2. Limits of use#

The theoretical framework is homogeneous linear elasticity

For ZZ1, 2D modeling (plane, axisymmetric constraints and deformations) and 3D models are allowed while for ZZ1, only 2D modeling (plane, axisymmetric stresses and deformations) are allowed.

Element types:

triangles with 3 and 6 nodes,

quadrangles with 4, 8 and 9 knots.

For ZZ2, the mesh should only have one type of elements.