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Applied gravity in one sirection and then the other

Applied gravity in one sirection and then the other

Applied gravity in one sirection and then the other

(OP)
I am working with a model of a circular disc with a bowl on one side (off axis concave mirror). What I am trying to do is apply a gravity load, import the displaced geometry then create a new study with a reverse gravity load. The idea is to bring the displacement back to 0, but this is not happening. Any ideas?

RE: Applied gravity in one sirection and then the other

Maybe the complex curved surface created by the displaced shape is stiffer than the original flat disk?

I'm trying to think my way backwards through the stiffness matrix generation, and I dont know for sure, but I dont think the math will be the same "forwards" as "backwards" like you're doing. I could be wrong.

Maybe try a very simple case and see if it works for that?

Beat to fit, paint to match.

RE: Applied gravity in one sirection and then the other

(OP)
Kellnerp - no plastic deformation..

I was thinking that the imported geometry might not have enough strain to actually import correctly as the max displacement is only around 50nm.

Thanks for the suggestion mrpi, I will try a much simpler case.

RE: Applied gravity in one sirection and then the other

If you have significant geometric stiffening then you need to turn on that switch if using a static analysis. If the behavior of the structure is such that there is snap through then you might need to do non-linear using the Riks method and largedisplacements.

If you run non-linear you can do the whole thing  in one run.

Is the geometric displacement of the nodes much greater than that due to elastic strain?

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