Controlling FEA Output

If FEA files, the Output command defines which results are written to the output text file. Some of the output options can be restricted to selected nodes.

Scripted Input Files

The Output command is used to determine what FEA calculation results are in the output file. The format is

Output (prop1),(out1),<(prop2)>,<(out2)>,...

where the arguments are given in pairs: ((prop1),(out1)), ((prop2),(out2)), etc.; each (prop) value gives a calculation result. The options are:

1. displacements - output nodal displacements.
2. forces - output nodal forces calculated in each element.
3. elementstresses - output all components of stress calculated in each element and surface tractions in each interface element.
4. nodalstresses - output average stresses at the nodal points.
5. reactivities - output reaction forces at all nodes with fixed boundary conditions.
6. energy - output strain energy of each element and the total strain energy.

Each (prop) option is followed by an (out) option that determines what is included in the output file. The options are:

• yes - fully output the preceding option. Fully output means to output all nodal results and all element results.
• no - completely omit the preceding option.
• selected - only output result relevant to selected nodes, which are selected as described below. If no nodes are selected, this mode will result in no output for that option. The "reactivities" and "energy" options can only be "yes" (or 'Y') or "no" (or 'N'); if "selected" (or 'C') is used it will be treated as "yes" (or 'Y').

The default output settings will be "yes" (or 'Y') for all options except "reactivities", which will be "no" (or 'N'). If you use an Output command, it only needs to enter those options you want to change from these default settings.

Selecting Nodes

You can select nodes for any output option that uses the "selected" style with the following methods:

SelectLine command

The SelectLine command is used to select all nodes near a line and it is available in two versions:

SelectLine (x1),(y1),(x2),(y2),<(tolerance)>

or

SelectLine (id)

where

• (x1,y1) and (x2,y2) give the coordinates (in length units) for the points at the beginning and end of the line (or (R,Z) coordinates if axisymmetric).
• (tolerance) is an optional tolerance (in length units) to include nodes within that distance of the line. If omitted, a tolerance will set based on small fraction of the smallest element size in the mesh.
• (id) is the id of a previously defined path.

SelectPoint command

The SelectPoint command is used to select a single node and it is available in two versions:

SelectPoint (x),(y)

or

SelectPoint (id)

where

• (x,y) gives the coordinates (in length units) for a point (or (R,Z) coordinates if axisymmetric). The node closest to that point will be selected.
• (id) is a previously defined key point. The node at that key point will be selected.

Select command

A Select command (on a line by itself with no arguments) can be used within FixLine or FixPoint Commands to select all nodes on the defined line or the single node at the defined point.

XML Input Files

The Output and Select commands are used to determine what FEA calculation results are in the output file. The format within the header is:

<Output>YYYYNY</Output>
<Select node='1'/>
<Select node='23'>

The text of the Output command has 1 to 6 letters, each of which must be 'Y', 'C', or 'N' — 'Y' means that result is fully included in the file; 'C' means that result is conditionally included only if it is relevant to a preselected node; and 'N' means that result is not included in the file. The six output options are listed above.

To preselect nodes for the 'C' option, include one or mode Select commands in the header using its node attribute to specify the node by number. This method, however, is typically not very useful. A better way to select nodes in XML files is to select them using a select='1' attribute on BCLine or BCPt Commands used for create boundary conditions.