Model with viscous connections

[felicegiordano95]

Hi, I am attaching a very simple 3D model in which I modeled an elementary structure with viscous connections where the viscous portion is given by material properties and the viscous behavior is only axial and to block the vertical displacements (the only direction I have to block) I used the twonodelink. An error is generated for the analysis and I cannot finish the analysis.
Thanks for your help

[felicegiordano95]

sorry I forgot to write that the error it generates is this "Element must be an" interaction "and not" Edge "" and I can't solve it.
Thanks again

[marafini.f]

You applied the twoNodeLink element to an edge, it need to be applied to the interaction.
Moreover, the uniaxial.Viscous.damper material cannot be applied directly (even more to the interaction and not to the edges), but you need to create the twoNodeLink material, as it was suggested in this other post.

viewtopic.php?f=54&t=1993

[felicegiordano95]

Hello,
if I have a viscous interaction between a beam and a column, I have to characterize the connection both for the viscous part in one direction and in the other directions, blocking the displacement. To characterize the viscous behavior I create a line and assign to it the physical property of a viscous element and at the same time between the nodes of the beam and the column I create an interaction and assign the viscous interaction. In the same way I will have to do for the Twonodelink link, creating element properties, physical properties also a condition to be assigned to the link in which I block the movements between the two nodes and I cannot do all this in a link between two nodes. I hope it was clear. I am attaching the elementary model on which I am trying to make this link.
Thanks for your attention

[marafini.f]

Dear felice,

I suggest you incorporate the recommendations I gave you in my previous post and try again.

[felicegiordano95]

Hi, I corrected the interactions as you told me, but I still can't start the analysis on the model because I can't join the elements connected with the interaction to the rest of the model, and the error appears before I start the analysis in which multiple geometries are detected. I enclose the whole model in case you can help me, thank you very much.

[marafini.f]

Dear felice,

I think you are very confused about what you want to achieve with your models. We can support you with your models, but you have to put in the effort. So I am going to ask you questions.

How can you join disconnected geometries? What about merging them?

Your viscous damper has concrete in the other directions as a material, the concrete you used has not tensile strength. Moreover, you are in 3D and you just defined the displacement DOFs for your damper, do you think your structure is stable and determined (isostatica)? Or undetermined (iperstatica)? Or maybe it's unstable in the way you defined it (labile)?
If you define a different elastic material with a very stiffness and assign it to the other DOFs of your twoNodeLink you can get a rigid constraint with damping in the global x-direction, is this what you want to achieve?

Did you put the control node correctly in the selection set or there is something else in this?

Plus, are you sure about the direction and application points of the forces of the pushover analysis you applied? How do you expect your results to look like?
I am sure this is not what you were expecting, but just fixing the above-mentioned issues and running your model, this is what you get.

2.png (345.55 KiB) Viewed 4429 times

To answer your other post, to see the stress in the plates you need to request section.fiber.stress in the recorder and then create a fiberPlot in the postProcessor once you have your result database.
To align the travetti you can use this options in the RectangulaFiberSection.

1.png (81.6 KiB) Viewed 4429 times

[felicegiordano95]

Hello,
I tried to fix the model and inserted the viscous links. The analysis to be conducted is dynamic and therefore I have inserted a timeseries (PATH). No error is generated when the analysis is launched but it doesn't work in the end.
Thanks for your help

[marafini.f]

Dear emilio,

could you give me the loading conditions of your slabs (analisi dei carichi), and send me the model after you fixed the missing column error?

Thank you
Francesca

[felicegiordano95]

Dear Francesca,
sorry I don't know why the error for the column has not been fixed, I have fixed the element in the file that I am attaching. I should do a modal analysis and then I inserted a part of the vector that identifies me a part of the earthquake, so I don't use static forces in the analysis. At some point there is the writing "WARNING No Numberer type exists (Plain, RCM only)" and I can't unlock the analysis.
Thank you for your help.