mesh refinements...
mesh refinements...
(OP)
HI all,
I need some help on a problem that I'm not sure to explain.
I have a plate with a rib.
I put a normal force to the rib.
The finer my mesh will be, the higher the stress I have... I Thought it would stop but no....
I think it's a singularity (perfect sharp angle 90°) but not sure...
This is not converging...after several refinement (exagerated)... ;)
Thx all
Caviac
I need some help on a problem that I'm not sure to explain.
I have a plate with a rib.
I put a normal force to the rib.
The finer my mesh will be, the higher the stress I have... I Thought it would stop but no....
I think it's a singularity (perfect sharp angle 90°) but not sure...
This is not converging...after several refinement (exagerated)... ;)
Thx all
Caviac





RE: mesh refinements...
RE: mesh refinements...
RE: mesh refinements...
assuming:-
1). your high stress is at the join of the rib to the plate
2). element type used is shells
3). rib is normal to the plate
3). normal force, is normal to the rib i.e. bending the rib
Then effectively the plate is seeing loading along a knife edge, this is a singularity and stress will not converge with mesh refinement.
Instead, model the structure in solids and include fillets and welds... then apply the loading as a distributed pressure.
RE: mesh refinements...
Try with a simple model you will see.... ;)
I will try with a fillet, I suppose it would be OK.
Thx
caviac
RE: mesh refinements...
RE: mesh refinements...
I have this kind of geometry :
_
| |
| | <- force distrib. on the surface.
| |
-------------- -------------
clamped | |clamped surface
------------------------------
A base with a rib on it...
And now you mesh it with 3D elements solid.
You solve it once for one element in the thickness for example.
You note the results.
You refine the mesh and solve it again.
...etc....
it seems the model gets high stress at the base that increase each time without converging ...
RE: mesh refinements...
What elements are you using? linear or parabolic ?, hex or tet ?
RE: mesh refinements...
ht
RE: mesh refinements...
The last one is interesting and we have made the same conclusions and verify it in theory/practices on calculations.
It's OK for us.
Thx again !