ALE Nodal Coupling instead of CLIS

[Furkan Keleş]

Dear all,

I am modelling an explosion event where solid parts coupled to ALE fluids are highly deformed. I have been using Constrained Lagrange in Solid keyword for this model and had a lot of issues with coupling.
Recently, I have started using ALE Nodal Coupling Penalty keyword to achieve the same coupling between solid parts and explosive. With this keyword, my results are slightly exaggerated but it runs relatively smooth and without any problem. I also never had any leakage problem with this keyword.
Is this keyword(ALE NODAL COUPLING ...) valid for solid-ale coupling? Am I missing something?
If so, what are the advantages of Constrained Lagrange in Solid keyword over ALE NODAL COUPLING since it is the recommended keyword for ale-solid coupling?

Regards,

Furkan

[l...@schwer.net]

From the User Manual Volume I

"Purpose: This command provides a penalty coupling mechanism between ALE materials and non-ALE (structure) nodes. The structure nodes may belong to Lagrangian solid, shell, beam, thick shell, or discrete (*ELEMENT_DISCRETE_SPHERE) elements. In contrast to *ALE_COUPLING_NODAL_CONSTRAINT, EFG, SPG, and SPH nodes are supported."

The keyword is *ALE_COUPLING_NODAL_PENALTY. --len

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[James M. Kennedy]

Dear Furkan,

https://ftp.lstc.com/anonymous/outgoing/jday/manuals/DRAFT_Vol_I.pdf

*ALE_COUPLING_NODAL_CONSTRAINT_{OPTION}

Purpose: This keyword activates constraint coupling between ALE materials (master) and
non-ALE nodes. The slave nodes may belong to Lagrangian solid, shell, beam, thick shell,
or discrete sphere (see *ELEMENT_DISCRETE_SPHERE) elements. In contrast to *ALE_-
COUPLING_NODAL_PENALTY, caution should be exercised in connection with EFG and
SPH nodes, as meshless methods generally do not satisfy essential boundary conditions,
leading to energy dissipation.

Chen, H., and Wang, J., "LS-DYNA ALE Nodal Coupling", 12th International
LS-DYNA Users Conference, Dearborn, Michigan, June, 2012.

http://www.dynalook.com/international-conf-2012/fsi-ale23-b.pdf

Chen, H., Wang, J., and Do, I., "LS-DYNA ALE/FSI Recent Developments",
13th International LS-DYNA Users Conference, Dearborn, Michigan, June,
2014.

http://www.dynalook.com/13th-international-ls-dyna-conference/fluid-structure-interaction/ls-dyna-r-ale-fsi-recent-developments

Xu, J., and Wang, J., "Interaction Methods for the SPH Parts (Multiphase Flows,
Solids Bodies) in LS-DYNA", 13th International LS-DYNA Users Conference,
Dearborn, Michigan, June, 2014.

http://www.dynalook.com/13th-international-ls-dyna-conference/fluid-structure-interaction/interaction-methods-for-the-sph-parts-multiphase-flows-solid-bodies-in-ls-dyna-r

Also, have a look at the relatively new keyword *ALE_COUPLING_NODAL_PENALTY.

*ALE_COUPLING_NODAL_PENALTY

Purpose: This command provides a penalty coupling mechanism between ALE

materials (master) and non-ALE nodes (slave). The slave nodes may belong to

Lagrangian solid, shell, beam, thick shell, or discrete (*ELEMENT_DISCRETE_
SPHERE) elements. In contrast to *ALE_COUPLING_NODAL_CONSTRAINT,

SPH and EFG nodes are supported.

---------------------------------------------

Perhaps these presentations associated with *ale_coupling_nodal_constraint
(similar input to *ale_coupling_nodal_penalty) might be of help.

Solution options for including the initial tension in the tendons (static implicit,
transient explicit, and Dynamic Relaxation solutions) and various methods for
coupling the tensioned tendons to the concrete (shared nodes, *CONSTRAINED_
LAGRANGE_IN_ SOLID, *ALE_COUPLING_NODAL_CONSTRAINT, and
*CONSTRAINED_BEAM_ IN_SOLID) were given. The concrete was modeled
using *MAT_159 (CSCM) with the default parameters for a concrete with unconfined
compressive strength of 41.37 MPa:

Schwer, L.E., "Modeling Pre and Post Tensioned Concrete", 14th International
LS-DYNA Users Conference, Dearborn, Michigan, June, 2016.

http://www.dynalook.com/14th-international-ls-dyna-conference/constitutivemodeling/modeling-pre-and-post-tensioned-concrete

A constraint based method to couple rebar in reinforced concrete has been a
popular method for Lagrangian simulations. However, modeling rebar in Arbitrary
Lagrangian-Euler (ALE) concrete has not been widely documented. This paper
aimed to investigate the effectiveness of two constraint based keywords, *ALE_
COUPLING_NODAL_CONSTRAINT and *CONSTRAINED_LAGRANGE_
IN_SOLID found in LS-DYNA to couple beam elements in ALE concrete.
This paper explored the option of explicitly assigning steel rebar with the ALE
concrete using *INITIAL_VOLUME_FRACTION to create a Multi-material
Arbitrary Lagrangian-Euler (MM-ALE) simulation:

Tay, S.K, Poon, J.K., and Chan, R., " Modeling Rebar in Reinforced Concrete for
ALE Simulations",14th International LS-DYNA Users Conference, Dearborn,
Michigan, June, 2016.

https://www.dynalook.com/conferences/14th-international-ls-dyna-conference/constitutivemodeling/modeling-rebar-in-reinforced-concrete-for-ale-simulations

Sincerely,
James M. Kennedy
KBS2 Inc.
June 9, 2022

-----Original Message-----
From: ls-d...@googlegroups.com [mailto:ls-d...@googlegroups.com] On Behalf Of Furkan Keles
Sent: Thursday, June 09, 2022 10:22 AM
To: ls-d...@googlegroups.com
Subject: [LS-DYNA2] ALE Nodal Coupling instead of CLIS