Configuring a substructure generation procedure

You can configure a substructure generation procedure to control the data that are generated for a substructure.

You cannot have a substructure generation step in a model that contains model instances.

This task shows you how to:

Create or edit a substructure generation procedure

  1. Display the Edit Step dialog box following the procedure outlined in Creating a step (Procedure type: Linear perturbation; Substructure generation), or Editing a step.

  2. On the Basic, Options, and Damping tabbed pages, configure settings such as substructure generation options and damping specifications.

Configure settings on the Basic tabbed page

  1. In the Edit Step dialog box, display the Basic tabbed page.

    (For information on displaying the Edit Step dialog box, see Creating a step, or Editing a step.)

  2. In the Description field, enter a short description of the analysis step. Abaqus stores the text that you enter in the output database, and the text is displayed in the state block by the Visualization module.

  3. In the Substructure identifier field, enter an integer between 1 and 999 that uniquely identifies this substructure in your model. Abaqus prepends a Z to the number you specify when it stores the substructure identifier in the model database.

  4. If desired, toggle on Evaluate recovery matrix for to enable selective recovery in your analysis, and do one the following:

    • Select Whole model to enable selective recovery for the entire model.

    • Select Region, and select a node set or element set from the list to enable selective recovery for a single set in your model.

Configure settings on the Options tabbed page

  1. In the Edit Step dialog box, display the Options tabbed page.

    (For information on displaying the Edit Step dialog box, see Creating a step, or Editing a step.)

  2. From the Generation Options, do any of the following:

    • Toggle on Compute gravity load vectors to calculate the substructure's gravity load vectors during substructure generation.

    • Toggle on Compute reduced mass matrix to generate a reduced mass matrix for the substructure.

    • Toggle on Compute reduced structural damping matrix to generate a reduced structural damping matrix for the substructure.

    • Toggle on Compute reduced viscous damping matrix to generate a reduced viscous damping matrix for the substructure.

    • Toggle on Evaluate frequency-dependent properties at frequency to evaluate frequency-dependent material properties in substructure generation. If you toggle on this option, you can also specify the custom frequency for the frequency-dependent properties.

  3. If you want to specify retained eigenmodes for generation of a coupled acoustic-structural substructure, toggle on Specify retained eigenmodes by, then select either Mode range or Frequency range.

  4. If you are specifying retained eigenmodes by mode range, enter the following data in the Data table to generate the list of eigenmodes:

    Start Mode

    The first mode number.

    End Mode

    The end mode number.

    Increment

    The increment in mode numbers between the start and end modes.

    For detailed information on how to enter data, see Entering tabular data.

  5. If you are specifying retained eigenmodes by frequency range, enter the following data in the Data table:

    Lower Frequency

    The lower limit of the frequency range or a single frequency, in cycles/time.

    Upper Frequency

    The upper limit of the frequency range, in cycles/time.

    For detailed information on how to enter data, see Entering tabular data.

Configure settings on the Damping tabbed page

  1. In the Edit Step dialog box, display the Damping tabbed page.

    (For information on displaying the Edit Step dialog box, see Creating a step, or Editing a step.)

  2. From the Global Damping Ratios options, specify the Field to which global damping will apply in this step:

    • Choose None to exclude the effects of global damping.

    • Choose All to apply global damping to all of the displacement, rotation, and acoustic fields in a model.

    • Choose Acoustic to apply global damping only to the acoustic fields in a model.

    • Choose Mechanical to apply global damping only to the displacement and rotation fields in a model.

  3. If you selected any Field setting other than None, do any of the following:

    • For the Alpha option, specify a value for the first Rayleigh damping ratio.

    • For the Beta option, specify a value for the second Rayleigh damping ratio.

    • For the Structural option, specify a value for the structural damping ratio.

  4. From the Viscous damping options, choose one of the following:

    • Choose None to exclude the effects of viscous damping altogether at the usage level.

    • Choose Element to activate only the generated condensed viscous damping matrix of the substructure.

    • Choose Factor to activate only the Rayleigh viscous damping.

    • Choose Combined to activate the combined generated and Rayleigh viscous damping matrix.

  5. From the Structural damping options, choose one of the following:

    • Choose None to exclude the structural damping matrix.

    • Choose Element to activate only the generated condensed structural damping matrix of the substructure.

    • Choose Factor to activate only the stiffness proportional structural damping matrix.

    • Choose Combined to activate the combined generated and stiffness proportional.

  6. When you have finished configuring settings for the substructure generation step, click OK to close the Edit Step dialog box.