Notes

PRRFOR has the same functionality as the PRRSOL command; use PRRFOR instead of PRRSOL when a FORCE command has been issued.

In a non-spectrum analysis, if either contact or pretension elements exist in the model, PRRFOR uses the PRRSOL command internally and the FORCE setting is ignored.

Because modal displacements cannot be used to calculate contact element nodal forces, those forces are not included in the spectrum and PSD analyses reaction solution. As a consequence, the PRRFOR command is not supported when constraints on contact element pilot nodes are present.

PRRFOR is not valid when using the amplitude or phase results set (KIMG = AMPL or PHAS on the SET command). Use PRRSOL instead.

PRRFOR is not available at a node when SHELL294 elements with a mismatch in layering are adjacent at that node, because internal constraints are used in that case. Use PRRSOL instead.

Using PRRFOR in a Spectrum or PSD Analysis (ANTYPE,SPECTR)

When using PRRFOR in a spectrum analysis, or in a PSD analysis when postprocessing 1-sigma results (loadstep 3, 4, or 5), the following message will display in the printout header:

(Spectrum Analysis summation is used)

This message means that the summation of the element nodal forces is performed prior to the combination of those forces. In this case, RSYS does not apply, and the reaction forces are in the nodal coordinate systems. Unlike PRRSOL, which retrieves the forces from the database, the PRRFOR command calculates the forces in the postprocessor.

The spectrum analysis summation is available when the element results are written to the mode file, Jobname.mode (MSUPkey = Yes on MXPAND).

The spectrum analysis summation is not available after reading a load case (LCWRITE, LCZERO, LCASE).

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