Learning Forum

[Janne]

Dear colleagues,

I have a question relating to different element types sharing nodes. For example, when I have a SHELL181 element that has 6 DOFs, and I connect that to SOLSH190 or HSFLD242 elements that have only 3 DOFs: how many DOFs the nodes actually have when I run the simulation? 

The same goes if I attach SHELL181 node to normal SOLID node.

Br, Janne

[Asitang Lahurikar]

Hi Janne,

Directly joining elements that have different DOF characteristics might lead to inconsistencies at the interface. It is important to note that the solution might not be able to transfer the appropriate forces or moments between various elements if the elements are inconsistent with one another. Even though this might not invalidate your analysis, you should be aware of what happens at the interface of two different element types.

However, if you wish to connect different elements, you can certainly do that. The SHELL181 and SOLID185 elements can be connected using contact with MPC formulation, where the target surface must be on the solid side and the contact surface/edge must be on the shell side. Depending on your requirements, you can also modify the type of constraint. To know more about the constraint types, refer to the Help document here -  14.5.3.3. Advanced Settings (ansys.com)

Hope this helps!
Regards,
Asitang

[Janne]

Hello Asitang,

Thank you for clarifying the issue for me. Let us forget about pure SOLID elements for the moment (I don't even use them). What I do have, is SHELL181 elements connected to SOLSH190 elements. The former has 6 DOFs and latter 3 DOFs. 

So, are you saying that one cannot say for sure that how many DOFs the shared nodes actually have? I did not use any special formulation, I simply made areas that are connected to volumes. The former I meshed with SHELLS and latter with SOLID-SHELLS using Ansys Mechanical APDL.

Thank you!

-Janne

[Asitang Lahurikar]

Hi Janne,

While there are 3 translational and 3 rotational DOFs for the SHELL181, SOLSH190 consists of 3 translational DOFs per node. If these two elements are connected, such that, they share common node(s), then the translations will be transferred across them but rotations won't. Please refer to this Forum thread for more information - Interface between solid and shell elements (ansys.com)

Regards,
Asitang