Shell Coating Solids (Strain Gage Simulation)

[HDFEA]

Hi,
I'm shell coating solid finite element geometry (parabolic tetrahedron elements)to do some correlation work with strain gage test data. Is there a good rule of thumb for what thickness the thin-shell element should be when you're trying to simulate a strain gage? What experiences have you had with this technique? Any other FE techniques available to get at surface strains? I'm running I-DEAS/UGS 11m2.

 

[OnlineFEASolver]

If you have sufficient mesh density then the extrapolated element nodal stress should equal the surface stress. I avoid shell coating since it adds unneccessary degrees of freedom to my models and is another source of modeling errors. Instead I just probe a consistent node where my strain gauge should be.

If you have to surface coat , then just anything really thin, like 0.01 mm and ignore any software warnings about ill-conditioned matrix.

Principal -

http://www.OnlineFEASolver.com

General FEA Consulting Services

 

[HDFEA]

Thanks for the information. I was getting singularites due to the very thin shell (0.001 inch thick) that I was using to coat the solids (as you mentioned).