Question about setting BeamContact2D Element for frictional interface

[youngkyu]

Dear support team members,

While simulating a soil slope on the elastic (duralmin) rigid box used in the centrifuge test,
I have a question about adding BeamContact2D element to the boundary highlighted as blue for modeling the frictional interface between the elastic wall (gray) and the soil slope (palevioletred).

I put the following commands to achieve the purpose,
- Interaction: node to element
- Physical properties: ContactMaterial2D
- Element properties: ContactBeam2D

When hitting the analysis button, I got the error "numbers of master node must be 2".

Is this related to what I incorrectly assigned the interface (node to element) to the right side of the soil domain in the figure?

Also, when switching to ContactBeam2dp for the element property,
I got the error "Matrix is Singular Numerically"

Please let me know what components I did not consider in my input file to achieve that goal.

One more quick question about the element property is that
what is a difference between BeamContact2D and BeamContact2dp?

Best Regards,
Youngkyu

[marafini.f]

Dear youngkyu,
I am not really an expert on this topic, but I can tell you that your model for sure has some errors in the geometry - Physical/Element property - interaction assignments.

In your model, you have an interaction between the soil and the beam you assigned the contact element to, with no conditions applied, nor element. Plus the beam you assigned the contact element to is not constrained. All of your geometry and interactions need to have element/physical properties and constraints to work, otherwise, something will be like "floating" and your model will be singular.

I am not sure if I am mistaken, but I think the contact element and physical properties need to be applied to interaction, not to a geometry. Plus, all those equalDOF that you defined, just try to do one thing at a time, first with elastic properties, and add slowly complexity to your model, so that you can check that everything is working well.

Maybe this webinar can be of help.
https://youtu.be/ZE453hKEA60


Let me know how it goes and I'll research a bit so I can help you better if you still have problems.
Enjoy your modelling
Francesca

[STKO Team]

I think that you need to revise your model as it seems that you are using components that are not necessary for your model.

If I understood correctly, you have a soil domain (brown material) inside a rigid box (gray material).
If that is the case, then:

• You don't need the BeamContact element. That element is needed when you want a contact between a SOLID element (slave) and a BEAM element (master). In your case you have a SOILD (soil) to SOLID (box) contact. You can use the ZeroLengthContactImplexASD in a node-to-node interaction, directly between the soil and box domains. We gave a webinar on that.
• I don't think you need the EDOF constraint for simulating the free-field and the dashpot at the base. Those kinds of boundaries are required when you want to model an elastic half-space, but in your case, the rigid box is not an infinite medium.