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3.To do the cut-boundary interpolation (and the temperature interpolation), the database must contain the geometry for the coarse model. Therefore, you must resume the database using one of the methods shown below, making sure to identify the name of the coarse-model database file:

Command(s): RESUME

GUI: Utility Menu> File> Resume from

For example, if the job name for the coarse-model analysis was COARSE, issue the command RESUME,COARSE,DB.

4.Enter POST1, which is the general postprocessor (/POST1 or menu path Main Menu> General Postproc). Interpolation can only be performed in POST1.

5.Point to the coarse results file (FILE or menu path Main Menu> General Postproc> Data & File Opts).

6.Read in the desired set of data from the results file (SET or menu path Main Menu> General Postproc> Read Results> option).

7.Initiate cut-boundary interpolation. To do so, use one of these methods:

Command(s): CBDOF

GUI: Main Menu> General Postproc> Submodeling> Interpolate DOF

By default, the CBDOF command assumes that the cut-boundary nodes are on file Jobname.NODE. The program then calculates the cut-boundary degree-of-freedom values and write them in the form of D commands to the file Jobname.CBDO.

To do temperature interpolation, use one of these methods, being sure to identify the name of the file containing all submodel nodes:

Command(s): BFINT

GUI: Main Menu> General Postproc> Submodeling> Interp Body Forc

Interpolated temperatures are written in the form of BF commands to the file Jobname.BFIN.

If real and imaginary data are involved, steps 6 and 7 must be performed twice. Issue the SET command to get the real data, followed by the interpolation step (CBDOF and/or BFINT). Issue the SET command with the field set to 1 to get the imaginary data, and repeat the interpolation step, this time writing the interpolated imaginary data to a different file.

For load-history-dependent problems, steps 6 and 7 can be performed multiple times at different data sets or substeps. The cut-boundary degree-of-freedom values of each data set will reside

in the same file but in different data blocks, separated by a :CBnn label (where nn is the cumulative iteration number of the results set used).

8.All interpolation work is now done, so leave POST1 (FINISH) and restore the submodel database (RESUME or menu path Utility Menu> File> Resume from). (Be sure to use the submodel database job name.)

9.2.4. Analyze the Submodel

In this step, you define the analysis type and analysis options, apply the interpolated degree-of-freedom values (and temperatures), define other loads and boundary conditions, specify load step options, and obtain the submodel solution.

The first step is to enter the solution processor (/SOLU or menu path Main Menu> Solution).

Then define the appropriate analysis type (usually static) and analysis options.

To apply the cut-boundary degree-of-freedom constraints, simply read in the file of D commands (created by CBDOF) using one of these methods (for example, /INPUT,,CBDO):

Command(s): /INPUT

GUI: Utility Menu> File> Read Input from

Similarly, to apply the interpolated temperatures, read in the file of BF commands (created by BFINT) using one of these methods (for example, /INPUT,,BFIN):

Command(s): /INPUT

GUI: Utility Menu> File> Read Input from

If real and imaginary data are involved, first read in the file(s) containing the real data, specify whether degree-of-freedom constraint values and/or nodal body force loads are to be accumulated, and then read in the file containing the imaginary data.

Specify that degree-of-freedom constraint values are to be accumulated:

Command(s): DCUM,ADD

GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> Replace vs Add> Constraints Main Menu> Solution> Define Loads> Settings> Replace vs Add> Constraints

Specify that nodal body force loads are to be accumulated:

Command(s): BFCUM,,ADD

GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> Replace vs Add> Nodal Body Ld

Main Menu> Solution> Define Loads> Settings> Replace vs Add> Nodal Body Ld

Be sure to reset the DCUM and BFCUM commands to their default status before proceeding.

It is important that you duplicate on the submodel any other loads and boundary conditions that existed on the coarse model. Examples are symmetry boundary conditions, surface loads, inertia forces (such

as gravity), concentrated force loads, etc. (see Figure 9.5: Loads on the Submodel (p. 252)).

Then specify load step options (such as output controls) and initiate solution calculations using one of these methods:

Command(s): SOLVE

GUI: Main Menu> Solution> Solve> Current LS

For most problems, exit the solution processor (FINISH) after the solution has completed.

For load-history-dependent problems, apply the cut-boundary degree-of-freedom constraints in the next data block in the file created by cut-boundary interpolation (CBDOF), and solve (SOLVE) as a new load step. Because it is a new load step, for any rate-dependent materials and transient analysis, the time value must match the time when cut-boundary interpolation occurred. This step can be repeated until all cut-boundary degree-of-freedom constraints are applied. Then, exit the solution processor.

The overall data flow for submodeling (without temperature interpolation) is shown in Figure 9.6: Data Flow Diagram for Submodeling (Without Temperature Interpolation) (p. 252).

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Figure 9.5: Loads on the Submodel

Figure 9.6: Data Flow Diagram for Submodeling (Without Temperature Interpolation)

9.2.5.Verify the Distance Between the Cut Boundaries and the Stress Concentration

The final step is to verify that the cut boundaries of the submodel are far enough away from the concentration. You can do this by comparing results (stresses, magnetic flux density, etc.) along the cut boundaries with those along the corresponding locations of the coarse model. If the results are in good agreement, it indicates that proper cut boundaries have been chosen; otherwise, you will need to recreate and reanalyze the submodel with different cut boundaries further away from the region of interest.

An effective way to compare results is to obtain contour displays and path plots, as shown in Fig-

ure 9.7: Contour Plots to Compare Results (p. 253) and Figure 9.8: Path Plots to Compare Results (p. 253).