Abaqus/Explicit Output Variable Identifiers

Except for the information in the status file, results can be obtained from Abaqus/Explicit only by postprocessing.

The tables in the following sections list all of the output variables that are available in Abaqus/Explicit. These output variables can be requested as either field- or history-type output to the output database (.odb) file or for output to the results (.fil) file (see Output to the Data and Results Files). In general, output variables that can be requested as field- or history-type output to an output database in ODB format can also be requested as output in SIM format (see The Output Database). When the output variables are requested for output to the results file, Abaqus/Explicit first writes these variables to the selected results (.sel) file and then converts the selected results file to the results file after the analysis completes.

This page discusses:

Notation Used in the Output Variable Descriptions
Direction Definitions
Principal Value Output
Tensor Output

Notation Used in the Output Variable Descriptions

The entries Field, History, and .fil in the output variable's description indicate the availability of the output variable. Field refers to a field-type output selection to the output database, History refers to a history-type output selection to the output database, and .fil refers to a results file output selection. The output variable can be written to the respective file if the word yes appears after the category name; no means that the variable is not available to that file.

Direction Definitions

The direction definitions depend on the variable type.

Direction Definitions for Element Variables

For components of stress, strain, and similar material variables, 1, 2, and 3 refer to the directions in an orthogonal coordinate system. These are global directions for solid elements, surface directions for shell and membrane elements, and axial and transverse directions for beam and pipe elements. However, if a local orientation (Orientations) is associated with the elements for which output is being requested, 1, 2, and 3 are local directions.

Direction Definitions for Nodal Variables

For nodal variables, 1, 2, and 3 refer to the global directions (1=X, 2=Y, 3=Z except for axisymmetric elements, in which case 1=R, 2=Z). Even if a local coordinate system has been defined at a node (Transformed Coordinate Systems), the data in the results file and the selected results file are still output in the global directions.

If nodal field output is requested for a node that has a local coordinate system defined, a quaternion representing the rotation from the global directions is written to the output database. Nodal history data written to the output database are always stored in the global directions.

Direction Definitions for Integrated Variables

For components of total force, total moment, and similar variables obtained through integration over a surface, the directions 1, 2, and 3 refer to directions in an orthogonal coordinate system. A fixed global coordinate system is used if the surface is specified directly for the integrated output request. If the surface is identified by an integrated output section definition (see Integrated Output Section Definition) that is associated with the integrated output request, a local coordinate system in the initial configuration can be specified and can translate or rotate with the deformation.

Principal Value Output

Output of the principal values can be requested for stresses, logarithmic strains, and nominal strains. Either all principal values or the minimum, intermediate, or maximum values can be obtained. All principal values of tensor ABC are obtained with the request ABCP, and the minimum, intermediate, and maximum principal values are obtained with the requests ABCP1, ABCP2, and ABCP3, respectively. For three-dimensional, plane strain, and axisymmetric elements all three principal values are obtained. For plane stress, membrane, and shell elements only the in-plane principal values are obtained for history-type output, and the out-of-plane principal value cannot be requested. Principal values cannot be obtained for beam, pipe, and truss elements, and principal values of plastic strains cannot be requested.

If a principal value or an invariant is requested for field-type output, the output request is replaced with an output request for the components of the corresponding tensor.

Tensor Output

Tensor variables that are written to the output database as field-type output are written as components in either the default directions defined by the convention given in Orientations (global directions for solid elements, surface directions for shell and membrane elements, and axial and transverse directions for beam and pipe elements), or the user-defined local system.

The components for tensor variables are written to the output database in single precision. Therefore, a small amount of precision roundoff error can occur when calculating the variables' principal values. Such roundoff error may be observed, for example, when analytically zero values are calculated as relatively small yet nonzero values.