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Running the fatigue analysis

Once all the parameters related to your fatigue analysis are defined, you may actually run the fatigue computation either in interactive or in batch mode.

Interactive mode

The interactive mode may be launched by clicking the Launch button placed in the lower-right corner of the Editing fatigue analysis pane. Note that with the interactive mode, the whole process is automatically run.

The flip side is that the GUI is frozen and you need to wait for the end to get any results.

Clearly, this interactive way is recommended for just beginners or for checking purpose when you know that the whole fatigue process is short enough. Otherwise, we recommend to use the batch mode.

Batch mode

In version V5R5, when the rainflow counting method is used , two options are available with the batch mode:

"All in one" option

This option is based on the .DSF file.

Once you have defined all the parameters related to your fatigue analysis, click OK in the lower-right corner of the Editing fatigue analysis panel to validate all the settings.

Right click on the fatigue analysis name from the Model browser, and select Generate DSF file from the pop-up menu that displays, as illustrated next.

Once your DSF file is created, you can run the GUI as a batch process through simple ASCII command files (.CMD) or using the Batch Processing form that is available from the Tools menu. Refer to the Batch commands to learn more about batch commands.

"Fatigue by load cases" option

The fatigue post-processing is performed in two steps:

  1. Compute the individual damage for every load case; whatever the probability associated with every load case, the computed damage will consider 100% of occurrence;
  2. Combine all individual damage with their probabilities to get the glabal fatigue results.

So, once you have defined all the parameters related to your fatigue analysis, click OK in the lower-right corner of the Editing fatigue analysis panel to validate all the settings.

Right click on the fatigue analysis name from the Model browser.

  1. For the fist step: select Generate Batch Jobs Queue (by load case) from the pop-up menu (see above);

  2. This creates a file with extension " Fatigue_Analysis_name.DBQ" that shall be imported into the Batch mode

  3. Run the batch mode using the number of CPUs available: by default eight load cases will be processed in parallel.

    A folder with the name of the fatigue analysis is created which gathers the specific subfolders for every load case.

  4. For the second step: select Generate Fatigue Combination Cmd from the pop-up menu (see above).

  5. This creates a command file that shall be imported and run into the Batch mode.

This command file triggers on a python procedure mainForScripts.py delivered with all python scrypts in $PATH_FOR_DEEPLINES\Exec\Python\Scripts

The procedure uses an input file directly created by GUI named " Input_Fatigue_Analysis_Name.csv " may be modified before launching the command in the Batch mode.

Its structure is quite simple, keywords are indicated by a star.

*TITLE

*Chem $PATH\repertory with the DSK file

*FATIGUE DSK file name

*By point True (default option, combination is done on every section points)

Load_CASE* Proba (-)** Note that 1 means 100%

_DLC1  Proba1_

_DLC2 Proba2_