[Sargam05]

Hello everyone,

I am running solidDisplacementFoam problem for thermal stress analysis. My solution is converged but not showing good agreement with analytical solution.

Simulation results shows 8-10% error with analytical solution. Does 8-10% error is fine for solid problems?

Has anybody an idea?

Regards,
Sangeeta

[bigphil]

Hi Sangeeta,

I presume you are referring to the "hollow cylinder with internal temperature" case as described by Timoshenko, Theory of Elasticity.

I tried this case and I found that the errors become very small (much much less than 1%) as you refine the mesh.

I have attached an graph showing a comparison between the results from a coarse and fine mesh.

To answer your question about "is 8-10% error ok?", in general for solid mechanics, it depends on the assumptions made in the analytical solutions (and in the numerical model). But for relatively straight-forward linear elastic and thermal elastic, the results should be very close to the analytical, especially as the mesh is refined.

Hope it helps,
Philip

[Sargam05]

Originally Posted by bigphil

Hi Sangeeta,

I presume you are referring to the "hollow cylinder with internal temperature" case as described by Timoshenko, Theory of Elasticity.

I tried this case and I found that the errors become very small (much much less than 1%) as you refine the mesh.

I have attached an graph showing a comparison between the results from a coarse and fine mesh.

To answer your question about "is 8-10% error ok?", in general for solid mechanics, it depends on the assumptions made in the analytical solutions (and in the numerical model). But for relatively straight-forward linear elastic and thermal elastic, the results should be very close to the analytical, especially as the mesh is refined.

Hope it helps,
Philip

Hi Philip,

Thanks a lot for the reply. Actually here I am solving another problem of thermal stresses for OpenFOAM validation. This problem is given in Timoshenko (page no. 399). This is for a rectangular plate.

I am going to email this case to you.

Thanks,
Sangeeta

[glupieri]

hello
I have tried to resolve the problem of the title, that is also a case of the tutorial,
by subjecting the 2D cylinder to the following boundary conditions:
for temperature T=100 in the hollow and T=0 at the outer patch,
for displacement D=0 tractionDisplacement (traction and pressure).

The results looks not as accurate as the ones of Dr. Cardiff/analytical case
that I have seen in this forum, even if I try to refine the grid.

Did somebody try the same tutorial case recently?
Thanks
Cheers

Guido