# ASSIGN

I/O Options and Subcase Information Entry Identifies external files and their contents.

For details regarding file specification information, refer to Comment 3.

## Format

ASSIGN, type, option1, option2, option 3

## Examples

ASSIGN, PUNCH, C:\CMS\h3ddmig.pch
ASSIGN, PUNCH, C:\CMS\h3ddmig.pch
ASSIGN, H3DDMIG, AX, C:\CMS\h3ddmig.h3d

## Definitions

Type Option1 Option2 Option 3 Description
AKUSMOD filename N/A   Identifies an external file from which to read the AKUSMOD fluid-structure coupling matrix.

If this is not defined, it is presumed that the AKUSMOD coupling matrix is to be found in the same directory as the solver input file and is given the file name, ftn.70.

Use of the AKUSMOD fluid-structure coupling matrix requires the presence of PARAM,AKUSMOD,YES.

DAC TID filename   Identifies an external .dac file from which to read the load history information for Fatigue Analysis.
In addition to ASSIGN,DAC entry the TID value used here should match the TID field of the FATLOAD Bulk Data Entry for this load history to be used in the fatigue solution.
Note: The LHFORMAT field of the FATLOAD entry should be set to DAC.
ENGINE SUBCASE ID filename   Identifies an external file from which to read modification commands to be applied on the intermediate Radioss Engine file translated in the EXPDYN solution.

SUBCASE ID=0 means EXPDYN subcases.

EXCINP SUBCASE ID filename   Identifies an external file from which to read the modal participation factors calculated by AVL/EXCITE for both transient and FRF residual runs, and GT-SUITE for transient runs.

While running an AVL/EXCITE or GT-SUITE analysis, an .INP4 file is generated that contains the modal participation factors. The .INP4 file can be used along with the original flex H3D file to recover stresses, strains, displacements, velocities, and accelerations from a dynamic analysis run (only transient analysis for GT-SUITE). The SUBCASE ID is used to specify which SUBCASE the modal participation factors should be used for.

GETDISP filename N/A   Identifies an external file from which the results of the selected subcases are recovered. An actual file with the name Filename should exist for GETDISP to work. This entry should be added to the corresponding subcase(s) whose results are to be restored. The solution process for the corresponding subcase will be skipped. This entry can be added to more than one subcase, wherein, the results for each such subcases will be restored from the corresponding files. The set of grids in the restart file can only be either the same as or a subset of the grids in the input deck. Results for any grid which does not have corresponding data in the restart file will be automatically set to zero.
Note:
1. The subcase results can be saved in a restart file using the ASSIGN,SAVEDISP command.
2. This is currently only supported for Linear Static Analysis.
3. Global subcase still needs to be present in the input file even if the restart is performed with GETDISP. In this case, the solution of global subcase will be skipped and the solution will directly be read from restart file.
4. Refer to Save and Restart in the User Guide.
H3DDMIG matrixname filename   This option can be used in two ways, to identify external nodal flex .h3dfile to read DMIG matrices, or for identifying flex body in residual run result recovery (in conjunction with modal participation results from AVL/EXCITE and GT-SUITE).
1. Identifies an external nodal *.flexh3d file from which to read DMIG matrices. Provides a prefix (matrixname) for the matrices contained therein, and the path to and the name of the *.flexh3d file. All of the matrices in the .h3d file are used in the analysis by default. If only some of the matrices are to be used, use the K2GG, M2GG, K42GG, and B2GG data to specify which matrices are to be used. The unreferenced matrices will not be used in this case.
2. Identifies a flex body in the residual run which can be used in conjunction with ASSIGN,EXCINP which identifies the corresponding INP4 file from AVL/EXCITE or GT-SUITE for results recovery.

H3DCDS matrixname filename   Identifies an external file from which to read complex dynamic matrices for a CDS residual run. Provides a prefix (matrixname) for the matrices contained therein and the path to and the name of the filename_CDS.h3d file. All of the matrices in the filename_CDS.h3d file are used in the analysis.
H3DMBD Flex Body ID filename   This option can be used in three ways, to identify flex body for result recovery or in further OS-MBD analysis in the PFBODY Bulk Data Entry, or in fatigue analysis based on the recovered stresses.
1. Identifies an external nodal flexh3d file which contains the analysis recovery information for displacements, velocities, accelerations, stresses and strains. Provides a Flex Body ID for the information therein, and the path to the name of the flexh3d file.
2. The identified .h3d file (*.h3d or *_recov.h3d) can also be used as a flex body in OS-MBD analysis. This can be activated by referencing the Flex Body ID on the BID field of the PFBODY Bulk Data Entry. In such cases, the included flex body (ASSIGN, H3DMBD, Flex Body ID) is used in the analysis and the PFBODY information for flex body generation is not used.
3. The identified flexh3d file (after multibody analysis with flexbody in MotionSolve) can also be used in conjunction with a Fatigue subcase to generate fatigue results using the recovered stresses.
Note: The EL2PROP Bulk Data Entry is required to define property data to the element set from the flexh3d file.

Refer to Create Output for Third Party Software and Recover MBD Analysis Results for more information.

H3DRES ID filename   Identifies an external .h3d file for the following applications:
• To read frequency response results for a Random Response Analysis.
• To identify the .h3d file containing buckling modes or displacement results. The ID defined on this entry can be used by an IMPORT entry to point to this particular .h3d file. For more information, refer to the IMPORT entry.
• To read initial stresses. The ID defined on this entry can be used by an INISTRS Bulk Data Entry to point to this particular .h3d file. For more information, refer to the INISTRS Bulk Data Entry.
• To import results from the global model in case of submodelling. For more details, refer to Two Step Modeling in the User Guide.
• To import results from a linear static analysis subcase. A dummy linear static subcase with IMPORT can be present in the model which contains the ASSIGN,H3DRES entry, and the output can subsequently be used for Fatigue Analysis.
HFILE ID filename   Identifies an external file from which grid temperature at different time steps are prescribed.

Currently only PUNCH files are supported (SORT1 sorting method should be used while generating PUNCH files via THERMAL I/O Options Entry for compatibility with the HFILE option).

This file is used for Nonlinear One-Step Transient Thermal Stress Analysis (NL-OSTTS) where temperature is applied as thermal load.

The ID mentioned here is referenced on the HSI field of the TEMPT Bulk Data Entry.

INPUTT4 filename.op4 UNIT=ID (Fortran unit number of OP4 file) N/A This type is valid only for partitioned/part superelements.

Identifies an external OP4 file (filename.op4) from the DMIG matrices will be read.

Unlike OP4DMIG option, an external .pch file need not be specified.

The Fortran unit number specified here must match the definition in SEBULK (UNITNO field). Else this file will be ignored.

MATMDS Material Name Altair Multiscale Designer™ material model data filename.   Identifies an external material model file generated by Multiscale Designer. The “Material Name” of this ASSIGN entry can be referenced by the AMAT and AOPT fields of the MATMDS Bulk Data Entry.
MBDINP SUBCASE ID filename   Identifies an external file from which to read the modal participation factors calculated by MotionSolve for Transient Analysis.

While running MotionSolve, an .mrf file is generated that contains the modal participation factors. The .mrf file can be used along with the original *.flexh3d file to recover stresses, strains, displacements, velocities, and accelerations during a Transient Analysis run. The SUBCASE ID is used to specify which SUBCASE the modal participation factors should be used for.

MMO Model Name filename Number of DDM mpi processes for each corresponding model (for DDM parallelization within MMO) Identifies an external file to be included in a Multi-Model Optimization (MMO) run. "Model Name" is a user-defined label for the model, which can be used to qualify model-specific responses referenced on the DRESPM continuation lines of the DRESP2 and DRESP3 entries. The “Model Name” should be limited to 8 characters.
OP4DMIG name filename1.op4 filename2.pch This type is valid only for standard/external superelements.
Identifies an external OP4 file (filename1.op4) from which to read DMIG matrices. Additionally, you can also specify a punch file (filename2.pch) to read grids, coordinate systems, ASET/QSET/USET and SPOINT data. All of the matrices in the OP4 file are used in the analysis by default. If only some of the matrices are to be used, then use the K2GG, M2GG, K42GG, and B2GG data to specify which matrices are to be used. The unreferenced matrices will not be used in this case.
Note: If a punch file is not explicitly identified, then OptiStruct will use the punch file that has the same name as the OP4 file.
PUNCH filename N/A   Identifies an external file as the location to write DMIG data in PUNCH format.
RPC TID filname   Identifies an external .rpc file from which to read the load history information for Fatigue Analysis.
In addition to the ASSIGN,RPC entry, the TID value used here should match the TID field of the FATLOAD Bulk Data Entry for this load history to be used in the fatigue solution.
Note: The LHFORMAT field of the FATLOAD entry should be set to RPC and the CHANNEL field on FATLOAD should be defined.
SAVEDISP filename N/A   Identifies an external file to which the analysis results of the selected subcase are written. This entry should be added to the corresponding subcase(s) whose results are to be saved. This entry can be added to more than one subcase, wherein, the results for each such subcase will be saved in a separate file. For optimization runs, the results during the subsequent iteration will overwrite results of the preceding iteration.
Note:
1. The stored subcase results via ASSIGN,SAVEDISP can be restored using the ASSIGN,GETDISP command.
2. This is currently only supported for Linear Static Analysis.
3. Refer to Save and Restart in the User Guide.
STARTER SUBCASE ID filename   Identifies an external file from which to read modification commands to be applied on the intermediate Radioss Starter file translated in the EXPDYN solution.

SUBCASE ID=0 means EXPDYN subcases. 1

SIMPINP SUBCASE filename   Identifies an external .unv file generated while running a multibody dynamic analysis in SIMPACK. The resulting CMS flexbody modal participation factors in the .unv file can be used by OptiStruct to recover the dynamic displacements, velocities, accelerations, stresses and strains.

The SUBCASE ID is used to specify which SUBCASE the modal participation factors should be used for.

UPDATE filename N/A   Identifies an external file from which to read the updated cards after an optimization run. The external file can have any file extension, as long as it is an ASCII file that contains relevant data.

Currently, the following cards are supported:

GRID

MAT1, MAT2, MAT3, MAT4, MAT5, MAT8, MAT9, MAT10

PSHELL, PSOLID, PBAR, PBEAM, PELAS, PVISC, PDAMP, PBARL, PBEAML, PMASS, PROD, PBUSH, PBUSH1D, PAABSF, PWELD, PCOMPP, PSHEAR, PTUBE

CONM2

CDAMP4, CELAS4

MAP ID filename   Identifies an external result file to be used for the thickness mapping feature.

The ID used here must match ASID field of the MAP entry.

For the external result file, LS-DYNA (.k) and Nastran formats (.nas) are supported.

Note:
1. ASSIGN, UPDATE is intended for optimization output. It allows you to modify physical values which may typically be changed during optimization. For example, GRID point locations, material parameters, and so on. However, it does not allow changes to the actual model setup (for example, material ID on the property entry, or coordinate system ID on the GRID entry cannot be changed).
2. Multiple ASSIGN, UPDATE commands can be used to reference multiple files to be included in the model. However, data common to these multiple files will be overwritten. Exercise caution where multiple ASSIGN, UPDATE commands are specified. OptiStruct will print a WARNING message to the .out file, if data is overwritten.
3. The MID field of the PSOLID entry can be updated using ASSIGN,UPDATE. All other fields, except FCTN, are skipped. Assigning improper material type may result in an error.

1. For geometric nonlinear subcases, two types of modification commands are available in the external file defined with ASSIGN,STARTER/ENGINE: insert and replace.
insert
Usage
Inserts content between keywords /INSERT and /ENDINS to the intermediate Radioss Block deck at line number LINENUM.
Syntax
/INSERT,LINENUM
Content to be inserted
/ENDINS
replace
Usage
Uses content between keywords /REPLACE and /ENDREP to replace the content in the intermediate Radioss Block deck between line numbers LINENUM1 and LINENUM2.
Syntax