Applied gravity in one sirection and then the other

[DesertRatEngineering]

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?

 

[kellnerp]

Is this structure plastically deforming in case 1?

TOP
CSWP, BSSE

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[mrpi]

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.

 

[DesertRatEngineering]

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.

 

[kellnerp]

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?

TOP
CSWP, BSSE

http://www.engtran.com

http://www.niswug.org

http://www.linkedin.com/in/engineeringtransport

"Node news is good news."