STRAIN

I/O Options and Subcase Information Entry Used to request strain output for all subcases or individual subcases, respectively.

Format

STRAIN (sorting,format_list,form,type,location,extras_list,random,peakoutput,modal,Neuber, kpi, nlout=nloutid) = 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. SORT1 Results for each frequency/timestep are grouped together. SORT2 Results for each grid/element are grouped together. 11 blank (Default) For frequency response analysis, if element SET is not specified, SORT1 is used, otherwise, SORT2 is used; for Transient Analysis, SORT2 is used.
`format`	<HM, H3D, OPTI, PUNCH, OP2, PLOT, HDF5, blank>	HM Results are output in HyperMesh results format (.res file). Refer to Strain Results Written in HyperMesh .res Format. H3D Results are output in Hyper3D format (.h3d file). OPTI Results are output in OptiStruct results format (.strn file). PUNCH Results are output in Nastran punch results format (.pch file). Refer to Strain Results Written in Nastran .op2 and .pch Formats. OP2 Results are output in Nastran output2 format (.op2 file) Refer to Strain Results Written in Nastran .op2 and .pch Formats). 14 PLOT Results are output in Nastran output2 format (.op2 file) when PARAM,POST is defined in the Bulk Data section. Refer to Strain Results Written in Nastran .op2 and .pch Formats. If PARAM, `POST` is not defined in the Bulk Data section, this format allows the form for complex results to be defined for XYPUNCH output without having other output. HDF5 Results are output in the Hierarchical Data format, Version 5 (.h5 file). 18 blank (Default) 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>	VON Only von Mises strain results are output. PRINC, MAXS, SHEAR von Mises and maximum principal strain results are output. ALL (Default) All strain results are output. TENSOR All strain results are output. Tensor format is used for H3D output. DIRECT All strain results are output. Direct format is used for H3D output.
`location`	<CENTER, CUBIC, SGAGE, CORNER, BILIN, GAUSS>	CENTER (Default) Element strains for shell and solid elements are output at the element center only. CUBIC Element strains for shell and solid elements are output at the element center and grid points using the strain gage approach with cubic bending correction. SGAGE Element strains for shell and solid elements are output at the element center and grid points using the strain gage approach. CORNER or BILIN Element strains for shell and solid elements are output at the element center and at the grid points using bilinear extrapolation. 15 GAUSS Element (Total) strains and plastic strains for shell and solid elements are output at the Gauss integration points. 15
`extras`	<MECH, THER, PLASTIC> No default	MECH Output Mechanical strain (in addition to total strain). This output is only available for H3D format. THER Output Thermal strain (in addition to total strain). This output is only available for H3D format. PLASTIC Output Plastic strain (in addition to total strain). This output is only available for H3D format.
`random`	<PSDF, RMS, PSDFC> No default	PSDF Requests PSD and RMS results from random response analysis to be output. Only valid for H3D format. The "RMS over Frequencies" output is at the end of the Random results. RMS Requests only the "RMS over Frequencies" result from Random Response Analysis to be output. Only valid for H3D format. PSDFC Requests PSD, RMS and RMS (cumulative) results from random response analysis to be output. Only valid for the H3D format. The "RMS over Frequencies" output is at the end of the random results.
`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
`nlout`	<nloutid> 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
`option`	<YES, ALL, NO, NONE, SID, PSID> Default = ALL	YES, ALL, blank Results are output for all elements. NO, NONE Results are not output. SID If a set ID is given, results are output only for elements listed in that set. PSID If a property set ID is given, results for the elements referencing properties listed in the property set are output.

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.
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 ², PCH ²	H3D, OP2 ², PCH ²	H3D, OP2 ¹, PCH ¹	H3D, OP2, PCH
Corner Strain	H3D, OP2, PCH			H3D, OP2, PCH	H3D	H3D, OP2 ², PCH ²	H3D, OP2 ², PCH ²	OP2 ¹
Gauss Stress	H3D, OP2					H3D, OP2 ²	H3D, OP2 ²
Gauss Strain	H3D, OP2					H3D, OP2 ²	H3D, OP2 ²

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. The current support of HDF5 output format is:

In case of Linear Static and Normal Modes analysis,

The supported element types for element-based results (in .h5 format) are:

Result	Elements Supported
FORCE/ELFORCE	CBAR, CBEAM, CONROD, CTRIA3, CTRIA6, CQUAD4, CQUAD8
STRESS	CROD, CBAR, CBEAM, CONROD, CELAS1, CELAS2, CBUSH, CTRIA3, CTRIA6, CQUAD4, CQUAD8, CTETRA, CHEXA, CPENTA
STRAIN

Corner results are also available for the above results with CQUAD4 and CQUAD8 elements.

In case of Nonlinear Static analysis,

The supported element types for STRESS and STRAIN results (in .h5 format) are:

Result	Elements Supported
STRESS, STRAIN	CROD, CELAS1, CBAR, CBEAM, CTRIA3, CTRIA6, CQUAD4, CQUAD8, CHEXA, CPENTA, CTETRA

Corner results are also available for CQUAD4 and CQUAD8.
DISPLACEMENT, STRESS and STRAIN results are also available on-the-fly during the analysis, if the NLOUT entry is defined in the subcase.

In case of Linear Buckling analysis, only DISPLACEMENT result is available in .h5 format.

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.

¹ Only for shell elements.

² OP2 and PCH files for NLSTAT and NLTRAN analysis only include the results at the final timestep