6. Operands CHAM_GD and RESULTAT#

Calculated field values are stored in data structures called quantity fields. These quantity fields can be directly accessible (concept CHAM_GD) or can be found in a data structure combining several quantity fields (concept result).

A size field is a data structure that allows you to store fields defined at the nodes (cham_no_) or fields defined by elements (cham_elem_*). For fields by elements, we distinguish between fields defined at the nodes of the elements and fields defined at the points of GAUSS of the elements.

  • A resulting concept consists of one or more quantity fields. For example, at each calculation step, the displacement quantity field is stored in the result data structure. This structure is therefore a second-order matrix structure, one index of which is, for example, the list of calculation times and the other the set of calculated fields (displacements, constraints, deformations,…).

In this case, a quantity field is accessed by specifying a value of an access variable (order number, instant, frequency, mode number,…) and a field name (“DEPL”, “SIGM_ELNO”,…). There are several types of result concept: evol_elas, evol_noli, mode_meca,… Each corresponds to a list of fields and a list of legal access variables.

Given the structure of the result data, it is easy to understand that the printing possibilities that are available are those of the size fields, complemented by specific possibilities.

Notes:

  1. 3D meshes of type PYRAM5 and PYRAM13 are not available under I- DEAS. The values of the Aster fields associated with these meshes are therefore not written in the universal file created by the command IMPR_RESU in the format IDEAS.

  2. 3D mesh type HEXA27 is not available under I- DEAS. The values of the Aster fields calculated on this type of mesh are written on HEXA20 meshes; that is, only the values of the Aster fields are transferred to the first 20 nodes.

6.1. Operand CHAM_GD#

The values of the quantity fields are written in one or more datasets in the universal file:

  • dataset 55

for the fields at the nodes,

  • dataset 57

for element-wise fields at nodes,

  • dataset 56

for fields by elements at the points of GAUSS (in fact, we write constant fields by element by averaging on the points of GAUSS).

In I- DEAS™, some datasets are typed: displacements, constraints, deformations, temperature, pressure. We therefore group the components in order to write the typed datasets, then we write the other components in datasets of the « UNKNOWN » type.

Datasets of the « UNKNOWN » type contain a maximum of six components; for a magnitude field of n components we therefore write n/6 datasets.

6.2. Operand RESULTAT#

The RESULTAT operand allows you to print the fields contained in a result concept. For example, you can choose to print only certain fields (see the keyword: NOM_CHAM).

The result concept is written quantity field by quantity field in datasets 55, 56 or 57.