Mesh Convergence Study for new boundary conditions

[Tuman_1232]

Hello everyone,
I'm working on project where I need to perform linear static analysis.
After modeling process I made mesh convergence study and found stress values.
Now the boundary conditions has been changed.

Do I need repeat mesh convergence study process after boundary conditions changes?

As I see it, the answer is no. Since mesh convergence study just checks solution domain, it is not connected to the boundary conditions. It's more connected to geometry and types of elements.
But I'm not sure.

Thanks for your answers

 

[FEA way]

It depends on particular case but changed loads or boundary conditions may cause new stress concentrations so I think that it would be better to repeat mesh convergence study.

 

[btrueblood]

Agree that you should repeat convergence study, changes to bc's might highlight a previously unseen flaw in the model/mesh.

 

[IceBreakerSours]

Yes, you do.

Once you change a BC, you are solving a completely different mathematical model (i.e., the underlying partial different equation) which means the mesh convergence behavior cannot be guaranteed to be the same as your previous model(s). That said, if there are hard practical constraints, I suppose you could throw in a bunch of elements and offer appropriate caveats when communicating your results. It is not practical to do a mesh convergence analysis for every study.

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[rb1957]

for me, it depends.

if your mesh refinement exercise focused on regions of high strain rate change, then yes (as there'll be new areas of high strain rate.

if your mesh refinement 1/2d the size of all elements then you've got something to rationalise (that your model is well build).

Be very careful of using redundant fixed (hard, infinitely stiff) constraints. Fixed constraints can be used to take out rigid body motion. Any other constraints should be "firm" … finite stiffness, allowing a small (tiny) amount of deflection (as would occur in reality).

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