RD-T: 3160 Multi-Domain Analysis Setup

The objective of this tutorial is to show how to use the Multi-Domain technique.

The model used is a low speed pole impact on a bumper system. Note that the model is finely meshed (average mesh size = 2mm) in the region of the pole impact and coarsely meshed (average mesh size = 10mm) elsewhere.

rd3160_multidomainA
Figure 1.

In order to run this analysis using Multi-Domain technique, we have to split this model into two domains, one containing the finely meshed region and the other containing the rest. A node to node link (/LINK/TYPE4) is then specified at the boundary between the two domains.

These domains will be created using a pre-processor (using HyperCrash in this tutorial) and the options specific to Multi-Domain analysis will be added to the input decks through a text editor. A Multi-Domain main input file will also be created using a text editor.

Model Files

Before you begin, copy the file(s) used in this tutorial to your working directory.

Start HyperCrash

  1. Open HyperCrash.
  2. Set the User profile to RadiossV2022 and the Unit system to kN mm ms.kg.
  3. Set User Interface style as New.
  4. Set your working directory to where the downloaded file is located.
  5. Click Run.
  6. Click File > Import > Radioss.
  7. In the input window, select monodomain_0000.rad.
  8. Click OK.

Create Input Files

  1. Click Model > Control Card to set the Control Cards, as shown in the following images:

    rd3160_control_cards1
    Figure 2.

    rd3160_control_cards2
    Figure 3.

    rd3160_control_cards3
    Figure 4.
  2. Click the Tree tab and select the subsets of the fine-meshed region (subsets BB_fine1 (21), BB_fine2 (24), and fine_mesh (69)), then right-click, then click Export Selection.

    rd3160_fine_meshA
    Figure 5.
  3. In the Export Selection window, select the option to Add model’s control card not linked to any part, toggle Export geometry and select ALL POSSIBLE RELATED ENTITIES.

    export_selection_13
    Figure 6.
  4. Click Ok.
  5. Save the file as fine_mesh.
    This will write the file fine_mesh_0000.rad.
  6. Click Model > Control Card and enter the following Control Cards:

    rd3160_control_cards5
    Figure 7.
  7. Click the Tree tab and select the subsets/spotwelds of the coarse-meshed region, then right-click Export Selection.
  8. In the Export Selection window, select the option to Add model’s control card not linked to any part, toggle Export geometry and select ALL POSSIBLE RELATED ENTITIES.

    export_selection2_13
    Figure 8.
  9. Click Ok.
  10. Save the file as coarse_mesh.
    This will write the file coarse_mesh_0000.rad.

Expected Results


rd3160_results
Figure 12.