I can spot a few things that could be improved:
your movement is defined in positive Z-direction, which won’t squeeze the coin, but lift the plate
you define a physical contact between the coin base and the lower plate, but also fix the coin base with a constraint - this will probably over-constrain the system, but at least the contact is superfluous . Choose either the contact or the constraint
if you remove the bottom coin constraint than you only have the coin constrianed by contacts and this does not restrict the movement at all in X and Y directions (imagine you use two plates of ice - the coin will definitely slip away). I would use a small elastic support on the side of the coin
your model is perfectly symmetric, so you could save some core-hours (and headaches regarding the proper constraint on the coin sideways movement) by using a quarter model
Wow, I’m blaming that on the 1 am to 4 am time frame of project development
I tried initially without the x/y constraint on the bottom coin face but got errors that lead me to constrain it too and after constraining bottom coin face in x/y then the errors led elsewhere…
Aha, elastic support the coin, will do
Yep, will get to symmetry eventually but I had issues with the 1/4 model on that airship FEA project (where the constraints at symmetry planes would not seem to let the envelope expand realistically) and I did not want to go there again until I got something working, besides this FEA stuff is so much quicker than the CFD stuff I started my SimScaling with
Thanks Richard as always
So I tried: 1. Fixed ram movement direction (not responsible for the error and I think I would have quickly seen the error in my ways when a sim was completed and ram move up ) 2. Added x/y elastic support to bottom coin face (and removed fixed constraint an that face)
regarding the run for the full model, I think the scale of the movement is too large. You seem to want to apply a 12mm movement, but the coin seems only 1.2mm thick?
Regarding the cyclic symmetry: the setup is unfortunately not so straight-forward. Your system is basically over-constraint. The slave nodes of the cyclic symmetry condition are tied in normal direction already to the master elements on the opposite side. If you add a fixed value constraint on top there, you need to leave the normal direction free, otherwise you would constrain them twice. I can set up a working model later, but have no time at the moment. Please also make sure that the master and slave faces are correctly assigned based on the direction of the axis of rotation. You might find some useful information here: https://www.simscale.com/docs/simulation-setup/contacts/.
I changed the loading error and your model ran and converged for about .25 of the total time. Do you have any nonlinear material properties for the plastic your using? This may be part of the problem of why it cannot converge once is compressed the dist too much.
I am not sure what’s happening yet, but if you look at the mesh of the disk at the last time step, you can see the elements around the edge are elongated and growing the disk. The elements in the middle have not changed shape so the are not squishing correctly. This explains why your not seeing the larger change of shape you are expecting.
I’ll keep looking into it. I do know once you start deforming the elements too much the accuracy will go down and the convergence will be more difficult but I don’t think that is the problem yet.
Nice that you made some significant progress @DaleKramer!
As you added an elastic support to the lower surface of the coin, it actually does not deform symmetrically and the lower surface remains almost undeformed. I would probably use either both surfaces or the side face - btw. you can also use an orthotropic elastic support stiffness, and for example put a close to zero value in normal direction.
Wrt the small deformation limitation I would say in your case it should be fine as the normals of the cyclic symmetry plane do not change.
Your coin is also smaller than expected as you got some (relative to the final thickness) large contact penetration. You can try to increase the penalty factor or switch to a lagrangian contact to reduce the contact penetration.
I do not see Lagrangien options for contact type in the new WB.
Nothing in Numerics either…
I don’t see in any Documentation how to select a Lagrangien contact, I would like to try it…
I did see this but not sure what it means:
The contact solution method has to be chosen in a global sense in a simulation setup. Of course you can define different properties for different contact pairs, but it is not possible to switch between for example penalty and lagrangian contact.