RD-3160: Setting up Multi-Domain Analysis using HyperCrash

The objective of this tutorial is to show how to use the Multi-Domain technique. For more information on this technique, refer to Multi-Domain.

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

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 master input file will also be created using a text editor.

For a list of Multi-Domain options, refer to Multi-Domain Input.

For information on how to create links or connections between domains, refer to Multi-Domain in the User's Guide.

For more information on Multi-Domain Master Input, refer to Multi-Domain Master Input File.

Exercise

Step 1: Import Full Model

1.	Open HyperCrash 2017.

2.	Set User profile: to RADIOSS V14 and Unit system: to kN mm ms kg.

3.	Click Run.

4.	Click File > Import > RADIOSS to import the model monodomain_0000.rad.

Step 2: Create Input Files for the Two Domains

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

rd3160_control_cards1

rd3160_control_cards2

rd3160_control_cards3

2.	In the Tree, 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

2.	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

Click Ok.

4.	Save the file as fine_mesh. This will write the file fine_mesh_0000.rad.

5.	Click Model > Control Card and enter the following Control Cards:

rd3160_control_cards5

6.	In the Tree, select the subsets/spotwelds of the coarse-meshed region, then right-click Export Selection.

7.	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

Click Ok.

9.	Save the file as coarse_mesh. This will write the file coarse_mesh_0000.rad.

Step 3: Define Link between the Two Domains

In the original single model, the fine meshed region is connected to the coarse meshed region at both ends. When this model is split into two domains, we have to create a set of nodes in both the domains and link these node sets through the starter option (/EXTERN/LINK). This option has to be added to the two Starter input files using a text editor.

rd3160_domain_linkA

2.	Open the Starter file coarse_mesh_0000.rad and add the option /EXTERN/LINK, as shown below:

rd3160_begin

Note:

Two external links through node sets 1001 and 1002 have been added to this domain. These node sets were already defined in monodomain_0000.rad and exported to the two domains in Step 2.

3.	Open the Starter file fine_mesh_0000.rad and add the same options.

4.	Create a RAD2RAD input file input.dat defining the two domains and specifying the connections between them.

rd3160_def_domain

5.	The input files are now ready to be run using the Multi-Domain technique. For information on how to launch a Multi-Domain computation, refer to Multi-Domain.

Exercise Expected Results

rd3160_results

RD-3160: Setting up Multi-Domain Analysis using HyperCrash

RD-3160: Setting up Multi-Domain Analysis using HyperCrash

RD-3160: Setting up Multi-Domain Analysis using HyperCrash

Exercise

Exercise Expected Results

See Also: