VII.3.7 Extraction of dynamic response Results

In this example, one shows how it is possible to use the COM component to investigate the Results of Nastran dynamic response analyses.

The main difference between this example and the simple result extraction of section VII.3.4, is that one no-longer selects a sub-case for Result extraction. Instead, the extraction is done for all the sub-cases corresponding to the specified load case. When Results are printed in the cells, each line corresponds to one sub-case (i.e. to one frequency).

The different entities are sorted in the columns of the spreadsheet. This limits somewhat the number of FE entities for which the Results can be retrieved. This is why the Group in this case is specified directly by defining the integer IDs of their elements and nodes. The Group is also defined by the specification of the type of entities that are inserted (“EntityTypeSelector” ComboBox).

One also decided to extract only one component for each value.

When all the parameters have been defined, the “Extract” button performs the following operations in the corresponding VBA subroutine:

1.

The current NastranDb DataBase is retrieved using method “getDb” of FemDbIds spreadsheet.

2.

The names of the different sub-cases found in the XDB file are retrieved by method “getXdbScNames” of “NastranDb” class and stored in an Array of Strings. This list of sub-case is used for the reading of Results from XDB file.

3.

The names of selected load case, sub case and result type are used to import Results into the current DataBase. (One imports the Results for one load case, one Result type and all the sub-cases.)

4.

The Group corresponding to the type of entities and the list of integers defined at left part of the spreadsheet is created. This Group shall be used to extract Results from the DataBase.

5.

One uses method “getXdbLcInfos” of “NastranDb” class to obtain information on the load cases and sub-cases defined in the XDB file. The advantage of this method is that it provides the Results by increasing order of frequency and allows to retrieve easily the sub-case names, and their associated frequencies.

6.

Then a loop is done on the difference sub-cases. For each sub-case:

(a)

One extracts the Result on the selected Group.

(b)

One modifies the reference coordinate system if necessary.

(c)

One extract the selected component.

(d)

One retrieves the magnitude and phase for the different entities.

An Array with the data is build. The lines of the Array correspond to the sub-cases. The columns correspond to the different entities and to the magnitude and phase. This Array is stored in variable “ret”.

7.

The previous spreadsheet results are erased.

8.

The content of “ret” Array is pasted into the spreadsheet starting at line 51.

9.

The Results stored in the DataBase are removed by calling method “removeAllResults”.

10.

The two graphics are updated to plot the magnitude and phase for the different entities.

The spreadsheet works with complex Results only.