CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

OpenFoam Solid Stress Anlalisys

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By bigphil

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 30, 2012, 21:37
Default OpenFoam Solid Stress Anlalisys
  #1
New Member
 
Humberto
Join Date: Nov 2011
Posts: 5
Rep Power: 14
tokotico is on a distinguished road
Hello I am trying to do stress analysis of a Structural insulated panel, with SolidEquilibriumDisplacementFoam, without luck, here is case directory to download:

http://www.filedropper.com/sip

Somehow the solution is not generating any stresses inside the panel.

Please any help will be greatly appreciated.

Last edited by tokotico; September 10, 2012 at 19:52. Reason: Link Update
tokotico is offline   Reply With Quote

Old   August 31, 2012, 20:42
Default
  #2
Super Moderator
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,086
Rep Power: 34
bigphil will become famous soon enoughbigphil will become famous soon enough
Hi,

What errors are you getting?
I had a quick look at your case and your mechanical properties are not declared correctly (as in the $FOAM_TUTORIALS/stressAnalysis/solidEquilibriumDisplacementFoam/beamEndLoad case).
Also you have a defaultFaces patch which is empty.

Philip
bigphil is offline   Reply With Quote

Old   September 1, 2012, 00:21
Default
  #3
New Member
 
Humberto
Join Date: Nov 2011
Posts: 5
Rep Power: 14
tokotico is on a distinguished road
Quote:
Originally Posted by bigphil View Post
Hi,

What errors are you getting?
I had a quick look at your case and your mechanical properties are not declared correctly (as in the $FOAM_TUTORIALS/stressAnalysis/solidEquilibriumDisplacementFoam/beamEndLoad case).
Also you have a defaultFaces patch which is empty.

Philip
Thanks Philip, I checked the mechanical properties and it is exactly as the one on the tutorials, only changed the value for E and rho.

The defaultFaces patch I included it because it also exists on the tutorial.
the behavior is strange, the program only runs for nu = 0 and at the end the panel shows with 0 stress and 0 deformation everywhere. If I change nu=0.2 the solver crashes on iteration 550.

while solving it alwas shows
kineticEnergy = 0
kineticPower = 0
smi = 0
so basically nothing is happening I do not understand why!!!.
tokotico is offline   Reply With Quote

Old   September 1, 2012, 11:12
Default
  #4
Super Moderator
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,086
Rep Power: 34
bigphil will become famous soon enoughbigphil will become famous soon enough
Hi,

Ah the mechanicalProperties definition has changed in the standard OpenFOAM, OK that's fine.

As regards the defaultFaces patch, you have the boundary condition set to empty on this patch, but you can only use empty for 1-D or 2-D cases and your case is 3-D so I presume this boundary conditions is meant to be traction-free or something like that?

Also, has the case converged i.e. have you run the case for multiple time-steps OR have you increased the number of outer correctors?

Philip
bigphil is offline   Reply With Quote

Old   September 10, 2012, 19:46
Default Various Materials
  #5
New Member
 
Humberto
Join Date: Nov 2011
Posts: 5
Rep Power: 14
tokotico is on a distinguished road
Thanks for all your help Bigphil, I got rid of the empty patches thanks for the observation, but still it does not even converge.

I was wondering, How do I define two different materials right now I have

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object mechanicalProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

rho
{
type uniform;
value 1200;
}

nu
{
type uniform;
value 0.1;
}

E
{
type uniform;
value 5558500000;
}

planeStress no;

Thanks in advance for all your help!!!
tokotico is offline   Reply With Quote

Old   September 12, 2012, 05:36
Default
  #6
Super Moderator
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,086
Rep Power: 34
bigphil will become famous soon enoughbigphil will become famous soon enough
Hi Humberto,

To begin with, I would recommend you use "solidDisplacementFoam" in preference to "solidEquilibriumDisplacementFoam" even for steady state simulations (solidEquilibriumDisplacementFoams implementation tries to increase the convergence of steady state models using some tricks but I have found that it does not converge for Poisson's ratio's greater than zero). solidDisplacementFoam can simulate steady state by setting the d2dt2Scheme to steadyState.
This will probably fix your convergence issues.

As regards multi-material, you could replace the rho, nu, E uniform fields with non-uniform fields, however, I am not sure if there is a utility to do this. So I would recommend you use the solidMechanics solvers in OpenFOAM-1.6-ext which allow straight-forward simulation of multi-material bodies, however I am a bit biased .

The tutorial OpenFOAM-1.6-ext/applications/solvers/solidMechanics/tutorials/elasticSolidFoam/bimaterialCase shows how to do it.

Philip
bigphil is offline   Reply With Quote

Old   September 19, 2012, 09:13
Default
  #7
New Member
 
Daniel Chrastina
Join Date: Sep 2009
Location: Como, Italy
Posts: 9
Rep Power: 16
shpalman is on a distinguished road
Send a message via Yahoo to shpalman Send a message via Skype™ to shpalman
I also worked on modifying the solidDisplacementFoam solver to incorporate varying material parameters as fields in the same mesh, it "worked" in the sense that it converged and gave an output (identical to solidDisplacementFoam in the case of homogenous material), but I'm not sure about the physical reliability of the result.

I'm still using 1.7.x since when I first tried version 2 it tended to diverge. I might try 2.1.x.

Also I wrote something to extract the strain, if that's ever useful to anyone else.
shpalman is offline   Reply With Quote

Old   October 6, 2012, 20:15
Default
  #8
New Member
 
jon pry
Join Date: Oct 2012
Posts: 1
Rep Power: 0
jonpry is on a distinguished road
Quote:
Originally Posted by shpalman View Post
I also worked on modifying the solidDisplacementFoam solver to incorporate varying material parameters as fields in the same mesh, it "worked" in the sense that it converged and gave an output (identical to solidDisplacementFoam in the case of homogenous material), but I'm not sure about the physical reliability of the result.

Also I wrote something to extract the strain, if that's ever useful to anyone else.
I would be very interested in the codes for heterogeneous material parameters and strain extraction. Please post/send me contact info.

Thanks,

Jon Pry
jonpry is offline   Reply With Quote

Old   October 7, 2012, 08:13
Default
  #9
Super Moderator
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,086
Rep Power: 34
bigphil will become famous soon enoughbigphil will become famous soon enough
Quote:
Originally Posted by jonpry View Post
I would be very interested in the codes for heterogeneous material parameters and strain extraction. Please post/send me contact info.

Thanks,

Jon Pry
Hi Jon,

As I mentioned previously there are solvers in the solidMechanics branch of OpenFOAM-1.6-ext which are specifically designed for heterogeneous material properties. There has also been a paper recently published which is the basis of the adopted methods. Additionally strain fields are output.

Best regards,
Philip
wuwenbo likes this.
bigphil is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
problem with Min/max rho tH3f0rC3 OpenFOAM 8 July 31, 2019 10:48
Is there any anisotropic solver for solid stress analysis? stickjohnson OpenFOAM 6 October 31, 2011 15:51
What BC for a solid in OpenFoam? cristina87 OpenFOAM 2 May 11, 2011 19:15
Defining Solid Zones Not working elmcmaster FLUENT 3 May 22, 2009 08:14
OpenFOAM Training in Europe and USA hjasak OpenFOAM 0 August 8, 2008 06:33


All times are GMT -4. The time now is 01:52.