I/O Options and Subcase Information Entry STRESS - Output Request
Description
The STRESS command can be used in the I/O Options or Subcase Information sections to request stress output for all subcases or individual subcases respectively.
Format
STRESS (sorting,format_list,form,type,location,random,peakoutput,modal) = option
Argument Options Description
sorting <SORT1, SORT2> Default = blank
This argument only applies to the PUNCH format (.pch file) or the OUTPUT2 format (.op2 file) output for normal modes,
frequency response, and transient subcases. It will be ignored without warning if used elsewhere.
SORT1: Results for each frequency/
timestep are grouped together.
SORT2: Results for each grid/
element are grouped together (see comment 12).
blank: For normal modes analysis, SORT1 is used; for
frequency response
analysis, if no element SET is specified, SORT1 is used, otherwise, SORT2 is used; for transient analysis, SORT2 is used.
format <HM, H3D, OPTI, PUNCH, OP2, PATRAN, APATRAN,
HM: Results are output in
HyperMesh results format (.res file). Refer to Stress
Argument Options Description
PLOT, blank> Default = blank
Results Written in
HyperMesh .res Format.
H3D: Results are output in
Hyper3D format (.h3d file). Refer to Stress Results Written in HyperView .h3d Format.
OPTI: Results are output in
OptiStruct results format (multiple files).
PUNCH: Results are output in
Nastran punch results format (.pch file). Refer to Stress Results Written in Nastran .op2 and .pch formats.
OP2: Results are output in
Nastran output2 format (.op2 file) (see comment 15, and also refer to Stress Results Written in Nastran .op2 and .pch Formats).
PATRAN: Results are output in
Patran format (multiple files).
APATRAN: Results are output in Patran format (multiple files).
PLOT: Results are output in
Nastran output2 format (.op2 file) when PARAM, POST is defined in the bulk data section. Refer to Stress Results Written in Nastran .op2 and .pch Formats.
If PARAM, POST is not defined in the bulk data section, this format allows
Argument Options Description
the form for complex results to be defined for XYPUNCH output, without having other output. blank: Results are output in all
active formats for which the result is available.
form <COMPLEX, REAL, IMAG, PHASE, BOTH>
Default (HM only) = COMPLEX
Default (all other formats) = REAL
COMPLEX (HM only), blank:
Provides a combined magnitude/phase form of complex output to the .res file for the HM output format.
REAL or IMAG: Provides rectangular format (real and imaginary) of complex output.
PHASE: Provides polar format
(phase and magnitude) of complex output.
BOTH (HM only):
Provides both rectangular and polar formats of complex output.
type <VON, PRINC, MAXS, SHEAR, ALL, TENSOR, DIRECT> Default = ALL, TENSOR
VON: Only von Mises stress
results are output (HM, OPTI, and H3D only). PRINC, MAXS,
SHEAR:
von Mises and maximum principal stress results are output (HM and H3D only).
ALL: All stress results are
output.
TENSOR: All stress results are output. Tensor format is used for H3D output.
Argument Options Description
DIRECT: All stress results are output. Direct format is used for H3D output.
location <CENTER, CUBIC, SGAGE, CORNER, BILIN>
Default = CENTER
CENTER: Element stresses for shell and solid elements are output at the element center only.
CUBIC: Element stresses for shell elements are output at the element center and grid points using the strain gage approach with cubic bending correction. SGAGE: Element stresses for shell
elements are output at the element center and grid points using the strain gage approach.
CORNER or BILIN:
Element stresses for shell and solid elements are output at the element center and grid points using bilinear extrapolation.
random <PSDF, RMS> No default
PSDF: Requests PSD and RMS
results from random response analysis to be output for solid and shell elements only (See comment 13).
Only valid for OUTPUT2 and H3D formats. The "RMS over Frequencies" output is at the end of the Random results in the .h3d file and labeled "Simulation 1" in the .op2 file.
Argument Options Description
RMS: Requests only the “RMS
over Frequencies” result from random response analysis to be output for solid and shell elements only (See comment 13). Valid only for OUTPUT2 and H3D formats. It is labeled “Simulation 1” in the .op2 file.
peakoutput <PEAKOUT> Default = blank
PEAKOUT: If PEAKOUT is present, only the filtered frequencies from the PEAKOUT card will be considered for this output.
modal <MODAL> Default = blank
MODAL: If MODAL is present,
stresses of the structural modes and residual vectors are output to the PUNCH and OUTPUT2 files for modal frequency response and transient analysis.
option <YES, ALL, NO, NONE, SID, PSID>
Default = ALL
YES, ALL, blank: Stress results are output for all elements.
NO, NONE: Stress results are not output.
SID: If a set ID is given, stress
results are output only for elements listed in that set.
PSID: If a property set ID is
given, stress results for the elements referencing
Argument Options Description
property set are output.
Comments
1. When a STRESS command is not present, stress results are output for all elements for all linear static analysis, nonlinear quasi-static gap analysis, and inertia relief analysis subcases.
2. HyperView can internally derive STRESS results from the stress tensor when the options TENSOR or ALL are used. If the option DIRECT is used, it will display the stress result that were directly computed.
3. For elements that reference PCOMP or PCOMPG properties, the STRESS I/O option controls only stress results for the homogenized composite. The CSTRESS I/O option must be used to obtain ply stress and failure index results.
4. The Von Mises and Principal stresses are not available for frequency response analyses. 5. The form argument is only applicable for frequency response analysis. It is ignored in
other instances.
6. The forms BOTH and COMPLEX do not apply to the .frf output files.
7. Multiple formats are allowed on the same entry; these should be comma separated. If no format is specified, then this output control applies to all formats defined by OUTPUT or FORMAT commands for which the result is available. See Results Output for information on which results are available in which formats.
8. Multiple instances of this card are allowed; if instances are conflicting, the last instance dominates.
9. For optimization, the frequency of output to a given format is controlled by the I/O option OUTPUT. In previous versions of OptiStruct, a combination of the I/O options FORMAT and RESULTS were used; this method is still supported, but not recommended as it does not allow different frequencies for different formats.
10. For normal modes analysis output, if there is USET U6 data, the stresses for each residual displacement vector associated with the USET U6 DOF are also output to the H3D, PUNCH, and OUTPUT2 files.
11. For modal frequency response and transient analysis, the stress vectors associated with the residual vectors are written to the .op2 and .pch files after the modal stress vectors if the keyword MODAL is used.
12. In general, HyperView does not recognize the SORT2 format for results from the .op2 file. When results are output only in SORT2 format (<Result Keyword> (SORT2, OUTPUT2, … .)), the results are written by OptiStruct into the .op2 file in SORT2 format, but when the .op2 file is imported into HyperView, the results in SORT2 format are not recognized. Therefore, the SORT1 option is recommended for results output in OUTPUT2 format and SORT2 option is recommended for results output in PUNCH format.
13. PSDF and RMS von Mises stress results based on the Segalman Method are also written to the .h3d file for Random Response Analysis (only available in the H3D format).
14. The four-letter abbreviation STRE is interchangeable with STRESS.
15. format=OUTPUT2 can also be used to request results to be output in the Nastran output2 format (.op2 file).