IMPORT

I/O Options and Subcase Information Entry Used to identify the H3D files and frequency analysis subcases imported to directly run random response analysis.

Format

IMPORT(SUB=SUBID) = option

Definitions

Argument Options Description
SUB SUBID Subcase ID of the frequency subcase in the H3D file to be imported as the result for current subcase. 1
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.

Examples

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

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. If Stress/Strain/Force of 1D/2D elements, or rotation of Displacement/Velocity/Acceleration is required in subsequent Random Response analysis (using IMPORT and ASSIGN,H3DRES), then rotation output, via DISP(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 FRF H3D file will error out.