Material grouping is available in the LS-DYNA system for S-ALE simulations.
This feature allows you to group multiple parts that have the same material assignment from Engineering Data by using the Combine Materials option. The collision of two parts with material assignment WATER, where Combine Materials is set to Yes, is shown in the following animation.
Refresh the page to see the animation. View online if you are reading the PDF version of the help.
The Mechanical application achieves this by creating one ALE multi-material group ID (AMMGID) for parts with the same materials. For example, if two or more parts have material WATER, they will have the same AMMGID and therefore be tracked as one material.
Note: Engineering Data does not allow materials to have duplicate names. If you create a material called WATER and then duplicate it to create WATER2, meaning it has the same properties but a different name, then WATER and WATER2 will not be grouped together as they are considered different materials. In some instances, this can be used to your advantage as it prevents selected parts from being grouped.
To group parts with the same material:
Select the parts to be grouped and ensure they have the same material assignment from Engineering Data. You can view the material data by clicking the Engineering Data cell in the Project Schematic.
Set Combine Materials to Yes in the ALE Controls section of the Analysis Settings.
When running the analysis, parts with the same material are grouped using the keyword *SET_PART_LIST in the input file (input.k).
Note: Each data line under the *ALE_MULTI-MATERIAL_GROUP keyword represents one AMMG, with
the first line referring to AMMGID 1, second line AMMGID 2, and so on. idtype
0 indicates a part set and idtype 1 indicates an individual
part.
Ale.definition is also created in the same folder as the input file and contains the AMMGIDs and corresponding part IDs (PID), which are used for postprocessing graphics and plotting.