KDYN

I/O Options and Subcase Information Entry The KDYN command can be used in the I/O Options or Subcase Information sections to request dynamic stiffness output for all subcases or individual subcases respectively.

Format

KDYN(sorting,format,form,rotations) = option

Definitions

Argument Options Description
sorting <SORT1, SORT2, blank>

Default = blank

This argument only applies to the PUNCH format (.pch file) output for Frequency Response subcases. It is without warning if used elsewhere.

SORT1
Results for each frequency are grouped together.
SORT2
Results for each grid/element are grouped together.
blank
For frequency response analysis, if no grid SET is specified, SORT1 is used, otherwise, SORT2 is used.
format <H3D, PUNCH, blank>

Default = blank
H3D
Results are output in Hyper3D format (.h3d file).
PUNCH
Results are output in Nastran punch results format (.pch file).
blank
Results are output in all active formats for which the result is available.
form <REAL, PHASE, blank>

Default = REAL
REAL
Provides rectangular format (real and imaginary) of complex output.
PHASE
Provides polar format (magnitude and phase) of complex output. Phase output is in degrees.
blank
rotations <ROTA, NOROTA>

Default = NOROTA
ROTA
Rotational dynamic stiffness results are output. This only works for H3D format. Rotations are always output with translations for PUNCH.
NOROTA
Rotational dynamic stiffness results are not output. This only works for H3D format. Rotations are always output with translations for PUNCH.
option <YES, ALL, NO, NONE, SID>

Default = ALL
YES, ALL, blank
Dynamic stiffness is output for all grids.
NO, NONE
Dynamic stiffness is not output.
SID
If a set ID is given, dynamic stiffness is output only for grids listed in that set.

Comments

  1. When the KDYN command is not present, dynamic stiffness is not output.
  2. Dynamic stiffness is calculated as the reciprocal of displacement.
  3. KDYN output request is only supported for Frequency Response analysis.
  4. Results in binary format (.h3d) are always output in PHASE/MAG form, regardless of the options specified in the FORM field. The corresponding post-processors (HyperView/HyperGraph) can easily convert the PHASE/MAG format to the required formats. Results in ASCII formats are output in the specified/requested FORM.