Hello there, I am trying to model two stacked steel plates on top of two steel stubs (jacks). Plates will be used as bearing plates to support a big load from a structure above them. There is no connection between plates, they are not welded or anything just stacked. There is also no connection between the plates and the steel stubs (jacks) below. Plates just sit on the stubs. The surface between the plates and the plates and the sub is modeled as Hard Contact Pair. Load is applied on top as uniform pressure. If I remove one of the plates and run the model with Hard Contact between the plate and jacks, it works fine, but if I have the two stacked plates it comes up with weird results, and non-realistic behavior. Top plate is also rotating about its vertical axis. I can use a Tie connection between plates but this would be unrealistic and not match the actual condition.
Can you please help with thoughts and suggestions.
Too large or otherwise unexpected deformation ? Do you check the results with deformation set to True scale instead of Automatic ?
In static analyses, you should eliminate rigid body motions. Contact may not be sufficient for that (especially when it’s frictionless) and may leave initial RBMs. Then it’s good to add some supports (even just for individual nodes) or at least soft springs.
Thank you very much indeed! The friction between the plates helped tremendously. I should have thought about it. Initially as you suggested, I put one soft spring in the mid-point (nod) between the jacks but that did not do it. Probably needed it on several nodes. Quick follow up question: I used the model that you uploaded, and did not modify anything, just ran the analysis. Once ran I get the same picture as in your snippet but slightly different overall deflections in U3- vertical direction? Any reason why that may be? For example you had max=-0.2169", compared to my run -0.2228". Very small differences so not an issue, but just wondering as I did not change anything in the model, just run it. Please see snippet below. Thank you much again!
Yes, I made some changes, even for the screenshot in my first reply (hex elements for the stubs). Then I made further changes (particularly refined the mesh for the plates, switched to reduced integration elements and added friction) before saving and sharing the file in the second reply.
