IMPORT

I/O Options and Subcase Information Entry Identifies H3D files.

Identify the H3D files when:
  • In Random Response Analysis: The Frequency Response Analysis results can be imported directly to the Random Response Analysis. An additional fatigue subcase can be included in the model to conduct Fatigue Analysis using results from the Random Response Analysis subcase.
  • In Submodeling: The displacement results from the global model can be imported and mapped to a local model. An additional fatigue subcase can be included in the model to conduct Fatigue Analysis using results from the local model.
  • In Linear Static Analysis followed by Fatigue Analysis: The linear static results from an .h3d file can be imported within a dummy linear static subcase, followed by a Fatigue Analysis subcase which references the dummy linear static subcase.

Format

IMPORT(SUB=SUBID) = option

Definitions

Argument Options Description
SUB SUBID
Subcase ID
In case of Random Response Analysis, it is the Frequency Response Analysis subcase in the .h3d file to be imported as the result for current subcase. 1

An additional fatigue subcase can be included in the model to conduct Fatigue Analysis using results from the Random Response Analysis subcase.

In case of submodeling, it is the linear static subcase in the .h3d file from which results are to be imported and used for enforcing displacements in the current subcase. 2

An additional fatigue subcase can be included in the model to conduct Fatigue Analysis using results from the local model.

In case of Linear Static Analysis, results are imported from the linear static subcase in the .h3d file and assigned to a dummy linear static subcase. A subsequent Fatigue Analysis subcase can use the results from the Linear Static Analysis for Fatigue Analysis. 7
option <ASSIGN ID>

No default

 ID for the assigned .h3d file. ASSIGN, H3DRES is also required to assign the .h3d file with an ASSIGN ID.

Example 1

ASSIGN, H3DRES, 21, C:\RANDOM\FRA.H3D
SUBCASE       1
  ANALYSIS DFREQ
  IMPORT(SUB=11) = 21

Example 2

ASSIGN, H3DRES, 38, C:\static\global.H3D
SUBCASE       1
  ANALYSIS NLSTAT
  IMPORT = 38
  LOAD = 5
  SPC = 3
  NLPARM = 7

Comments

  1. SUB could be used to define the Subcase ID for which frequency response results are to be exported from the H3D file. If not specified, then the current frequency response subcase ID (either dummy/original) is adopted as default. If IMPORT is defined above all subcases, the SUB option in this global IMPORT entry would be ignored.
  2. Dummy frequency subcases or original frequency analysis subcases are required. Any loads defined in such subcases are ignored for the Random Response Analysis.
  3. If at least one IMPORT entry is defined in a model, then all frequency response subcases in the model should only be intended for Random Response Analysis. Alternatively, if there is no global IMPORT entry defined above the subcases, each frequency subcase requires an IMPORT card to define the ASSIGN ID explicitly. In such a setup, if one or more particular frequency subcase does not contain an IMPORT entry, then OptiStruct will terminate with an error.
  4. If the output for the MPC degrees of freedom are requested, the MPC card needs to be defined in either of the subcases.
  5. Frequency response results such as DISPLACEMENT, VELOCITY and ACCELERATION from the H3D file can be imported to the Random Response Analysis, using IMPORT and ASSIGN,H3DRES.

    If STRESS/STRAIN/FORCE of 1D/2D elements, energy output (ESE/EKE/EDE), or rotational output of DISPLACEMENT/VELOCITY/ACCELERATION is required in subsequent Random Response Analysis, then rotation output, (using either of DISPLACEMENT(ROTA), VELOCITY(ROTA), ACCELERATION(ROTA)), is required during the initial Frequency Response Analysis that generates the H3D file.

    In such cases, if rotation output is not active in the initial Frequency Response Analysis model, then the subsequent Random Response Analysis using IMPORT and ASSIGN,H3DRES pointing to the frequency response H3D file will error out.

  6. For more details regarding usage of IMPORT in submodeling, refer to Two Step Modeling in the User Guide.
  7. For more details regarding restart for Fatigue Analysis, refer to Restart for Fatigue Analysis in the User Guide.