STRAIN
I/O Options and Subcase Information Entry Used to request strain output for all subcases or individual subcases, respectively.
It can also be used to request electric field output for Structural Analysis with piezoelectric materials. For more information, refer to Piezoelectric Analysis in the User Guide.
Format
STRAIN (sorting,format_list,form,type,location,extras_list,random,peakoutput,modal,Neuber, kpi, creep, rate, SUBSYS, NLOUT) = option
Definitions
Argument | Options | Descriptions |
---|---|---|
sorting | <SORT1, SORT2> | 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.
|
format | <HM, H3D, OPTI, PUNCH, OP2, PLOT, HDF5, blank> |
|
form | <COMPLEX, REAL,
IMAG, PHASE,
BOTH> Default (HM only) = COMPLEX Default (all other formats) = REAL |
|
type | <VON, PRINC, MAXS, SHEAR, ALL, TENSOR, DIRECT> |
|
location | <CENTER, CUBIC, SGAGE, CORNER, BILIN, GAUSS> |
|
extras | <MECH,
THER, PLASTIC> No default |
|
random | <PSDF,
RMS, PSDFC> No default |
|
peakoutput | <PEAKOUT> Default = blank |
If PEAKOUT is present, only the filtered frequencies from the PEAKOUT card will be considered for this output. |
modal | <MODAL> Default = blank |
If MODAL is present, strain results of the structural modes and residual vectors are output to the PUNCH, OUTPUT2 and H3D files for Modal Frequency Response and Transient Analyses. |
Neuber | <NEUBER> Default = blank |
If NEUBER is present, the von Mises strain corrected using the Neuber rule are output to the H3D file. 16 |
kpi | <KPI>
Default = blank |
Key Performance Indicators for Strain results are output in the *.kpi ASCII file. 20 |
creep | <CREEP> Default = blank |
Creep strains are output to the H3D file. 23 |
rate | <RATE> Default = blank |
Strain rate it output to the H3D file. 24 |
NLOUT | <NLOUT_ID> No default |
ID of an NLOUT Bulk Data Entry. If present, the incremental output control parameters are taken from the referenced NLOUT Bulk Data Entry, instead of the one selected by Subcase Entry NLOUT, when results are written into the *_impl.h3d file. 21 For more information, refer to Comment 3 in the NLOUT Bulk Data Entry. |
SUBSYS | <SUBSYS_ID> No default |
ID of the subsystem. When used along a subsystem definition, this option generates an individual result file for each subsystem with results for that subsystem only. For more information, refer to the SET Bulk Data Entry. |
option | <YES, ALL, NO,
NONE, SID,
PSID> Default = ALL |
|
Comments
- When the STRAIN command is not present, no strain data is output.
- HyperView can internally derive strain results from the strain tensor when the options TENSOR or ALL are used. If the option DIRECT is used, it will display the strain results that were directly computed.
- The von Mises and Principal stress are not available for Frequency Response Analysis.
- For elements that reference PCOMP and PCOMPG properties, the STRAIN I/O Option controls only strain results for the homogenized composite. The CSTRAIN I/O Option must be used to obtain ply strain results.
- The form argument is only applicable for Frequency Response Analysis. It is ignored in other instances.
- The forms BOTH and COMPLEX do not apply to the .frf output files.
- Multiple formats are allowed on the same entry; these should be comma separated. If a format is not specified, this output control applies to all formats defined by the OUTPUT command, for which the result is available.
- Multiple instances of this card are allowed. If instances are
conflicting, the last instance dominates.
However, the SYSSETTING I/O Option Entry (MULTIPLEOUTPUT=YES) can be used in the input file or the Configuration File to request multiple formats of the same output request. For more information, refer to MULTIPLEOUTPUT in the SYSSETTING I/O Option Entry.
- For optimization, the frequency of output to a given format is controlled by the I/O option OUTPUT.
- The mechanical and thermal contributions to strain may be requested in addition to the total strain.
- 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.
- PSDF and RMS von Mises strain results based on the Segalman Method are also written to the .h3d file for Random Response Analysis (only available in the H3D format).
- The four-letter abbreviation STRA is interchangeable with STRAIN.
- format=OUTPUT2 can also be used to request results to be output in the Nastran output2 format (.op2 file).
- The GAUSS results are currently only
supported for H3D and OP2 files. CORNER results are not
supported in OPTI format. To display
CORNER/GAUSS strain results in HyperView, activate the Use Corner Results check box in
the Contour panel. CORNER and GAUSS results (Stress, Total Strain, and Plastic Strain) are supported for both Shell (including composite shells) and Solid elements.
Static Eigenvalue Direct Frequency Response Modal Transient/ Frequency Response Direct Transient Nonlinear Static Nonlinear Transient Response Spectrum Random Corner Stress H3D, OP2, PCH H3D, OP2, PCH H3D, OP2, PCH H3D, OP2, PCH H3D, OP2, PCH H3D, OP2** PCH** H3D, OP2**, PCH** H3D, OP2*, PCH* H3D, OP2, PCH Corner Strain H3D, OP2, PCH H3D, OP2, PCH H3D H3D, OP2** PCH** H3D, OP2**, PCH** OP2* Gauss Stress H3D, OP2 H3D, OP2** H3D, OP2** Gauss Strain H3D, OP2 H3D, OP2** H3D, OP2** * Only for shell elements.
** OP2 and PCH files for NLSTAT and NLTRAN analysis only include the results at the final timestep.
- Neuber corrected strains are calculated based on the von Mises stresses from elastic analysis, the Young's modulus, and the nonlinear material properties defined on the MATS1 Bulk Data Entry. Neuber Strain results are available as elemental results, grid point strains, Gauss point strains, and Corner Neuber strains. Both plastic strain and total strain output are available. Neuber Stress/Strain is supported for Static, Frequency Response, and Transient Analysis for H3D output.
- Equivalent plastic strain takes into account the z-component of strain tensor for shells. On the other hand, strain tensor output (even with plastic strain tensor) does not output z-component of strain tensor, which would cause the difference in equivalent plastic strain and von Mises based on plastic strain tensor.
- The HDF5 output is printed to a .h5 binary results file. For details of the supported analysis types and elements when the .h5 output format is requested, refer to the .h5 file.
- PSDF and RMS stress results are output in the element coordinate system in H3D file.
- KPI output includes maximum value for Strain with respect to the corresponding property. It is supported for linear and nonlinear static analysis only. Stresses and Strains are supported only for shells and solids. KPI output can also be output for a particular SET using the SID option.
- nlout=<nloutid> applies only to implicit nonlinear subcases.
- If an initial temperature (predefined outside of the subcases) is different from the temperature at the very beginning of a subcase and the resulting thermal expansion is nonzero, the thermal strain due to this temperature difference is counted.
- Element based creep strains are output when STRAIN(CREEP,H3D) is specified. If creep strain energy output is required, then ESE(CREEP,H3D) can be used.
- Support for strain rate output:
- Nonlinear Static and Nonlinear Transient Analysis
- Either equivalent total strain rate and equivalent plastic strain rate is output depending on TYPSTRT=0 or 1 in MATS1, respectively.
- Explicit Dynamic Analysis
- Both equivalent total strain rate and equivalent plastic strain rate are output.