Learning Forum

[andrewthanga]

• Two 'Single ALE material' contained in a lagrangian shell conatiner and seperated by a lagrangian shell wall 
• Both the ale material and lagrangian material have same or equivalent density
• ALE materials do not mix
• Is it possible to model Fluid solid interaction or ALE and Lagrangian coupling, when both the ALE and Lagrangian material have same or equivalent density?  

[Alex R.]

 

Hello, 

It should be possible to set up fluid-solid interaction (FSI) or ALE-Lagrangian coupling in LS-DYNA for two single ALE materials, even when their densities match the surrounding Lagrangian shell container and they are separated by a Lagrangian shell wall.

• Assign elform = 11 to your ALE materials in the *SECTION_SOLID card, which is required for multi-material ALE formulations.

 

• Define each ALE region separately (e.g., ALE 1 and ALE 2) so that they do not mix and can be coupled independently to different Lagrangian surfaces.

 

• Use *SET_MULTI-MATERIAL_GROUP to create two distinct multi-material groups: one for ALE 1 and another for ALE 2. Each group will contain the respective ALE material part or part set. This setup is necessary for targeted coupling.

 

Configuring FSI Interaction Cards

• Depending on your ALE solver (standard or structured), use either *CONSTRAINED_LAGRANGE_IN_SOLID or *ALE_STRUCTURED_FSI to define the coupling between ALE and Lagrangian domains.

 

• For each interface, define a separate FSI interaction card:

 

• One card for coupling ALE 1 to the outer walls and bottom.

 

• One card for coupling ALE 1 to the inner walls.

 

• One card for coupling ALE 2 to the inner walls bottom.

 

• When specifying the MCOUP parameter in these cards, use a negative integer (e.g., MCOUP = -N), where N is the ID of the *SET_MULTI-MATERIAL_GROUP corresponding to the ALE region you want to couple. This ensures that only the specified ALE multi-material group is coupled to the designated Lagrangian surface

 

Thanks,
Alex 

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