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Home > User Interface > Results Processing > General Post-Processing > Export of Modal Shapes Files (.MDS)

Export of modal shapes files

DeepLines and PoDeep allow you to export modal shape files (.MDS) used for instance as an input to SHEAR7. The following steps present how to create these files.

  1. A model is built with the GUI or a .LOG file is created manually.

  2. A modal analysis is first run with a large number of modes. The modal analysis doesnt distinguish the kind of modes (axial, torsion or bending) neither the direction (cross flow or in-line).

  3. Then, the post-processing of the modal analysis with DeepLinesGUI or Podeep allows you to have a look at the modes and to select the modes of interest for the VIV analysis;

  4. Finally, you may request the generation of the MDS file in one of two ways :

    a. Using Podeep;

    b. Using DeepLinesGUI.

For both, you can do it interactively or with a batch mode.

The process with the GUI is as follows :

Whichever post-processor is used or the selected mode (interactive or batch), you have to specify :

  • The modal analysis name to be post-processed;

  • Which Object is to be post-processed (the riser of interest);

  • The number of modes to extract.

Interactive mode:

As you open the .DSS file for Post-processing, a new tab named MDS File is available in the Request section (this is only available if a modal analysis has been successfully completed) :

You may select within this panel :

  • The object of interest.

  • The modes number(s) of interest, separated by ; or - if you need several modes.

  • The output MDS File name and directory (by default, it will created in your current working directory).

Three series of curves are then generated by a click on the button add MDS files, that you may visualize in the Graphics* section. The output MDS file name is also created.

*Modal displacement, slope and curvature are plotted versus the line normalized arc-length.

Batch mode

You must use the following syntax :

$PATH/DeepLinesGUI.exe mdsfile FILE_NAME

Where FILE_NAME is the name of the batch commands file whose structure is as follows :

DSS_FILE_NAME

[TYPE] MDS

[OBJECT] GenLine_1

[MODE_NUMBER]   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 &

  20 21 22 23 24 25 26 27 28 29

[OUTPUT_FILE_NAME] MDSFILE_NAME.txt

MDS file example

The .MDS file format is illustrated below :