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Applying pressure on surfaces

Posted: 24 Nov 2022, 15:42
by ufifilters@123
Hi all,
Does anyone know how to apply pressure on surfaces in linear elastic model of ElmerGUI?
There is only option for applying pressure on body properties (as body force).

Re: Applying pressure on surfaces

Posted: 24 Nov 2022, 19:46
by kevinarden
Elmer's model manual chapter 6
https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf

In boundary condition you can add pressure normal to surface or othe BC load conditions.
Normal Force Real
A force normal to the boundary is given with this keyword.

Re: Applying pressure on surfaces

Posted: 25 Nov 2022, 12:09
by ufifilters@123
Thanks Kevin

I have tried with normal force equivalent to pressure on the surface (pressure=normal force/surface area). With this option, results are not coming out to be correct. I am trying to find the gap.
Do you know the option of applying pressure directly on surfaces?

Re: Applying pressure on surfaces

Posted: 25 Nov 2022, 16:00
by kevinarden
Normal force applied to a surface boundary is pressure. Perhaps you can post your case and it can be checked.

Re: Applying pressure on surfaces

Posted: 22 Jul 2023, 18:25
by ufifilters@123
Thanks for the advice. It was helpful.

just curious to know if multi-body (3D) contact analysis is possible in Elmer using ElmerGUI.

I was trying to import two 3D models in the same file from Gmsh to ElmerGUI. The file had both necessary volumes and surfaces (physical entities) such as contact faces, loading faces, fixed faces, etc. But after loading was complete, I observed a tangled model with all the surfaces of the two bodies getting mixed. the different surfaces cannot be identified even from the left-side Boundary and Body options.
When I tried to import after -autoclean geometry command, the models could be observed clearly but only their surface boundaries were visible. All other physical surfaces created were lost.

Is there a way to deal with this issue? I was trying to implement a bonded (or glued) contact analysis.

PS, the mesh file size is over 1Mb. Any way to upload files over 1mb?

Re: Applying pressure on surfaces

Posted: 22 Jul 2023, 19:48
by kevinarden
You can upload large files to github, google drive, or other services that provide that capability.

Re: Applying pressure on surfaces

Posted: 22 Jul 2023, 19:54
by kevinarden
I believe multi-body contact analysis is possible in GUI, it is definitely possible in ElmerSolver. ElmerGUI only displays bodies by there attached boundary surfaces. However, ElmerSolver does not require every body to have a boundary. So in ElmerGUI you are really viewing boundary surfaces not bodies. Sometimes this can be confusing.

In ElmerGUI each input screen has a free text input field, anything you type there is added to that section, this allows you to add things that are not a part of the GUI application.
freetext.PNG
freetext.PNG (4.48 KiB) Viewed 908 times

Re: Applying pressure on surfaces

Posted: 28 Jul 2023, 09:40
by ufifilters@123
Yes, I have also observed that ElmerGUI displays only boundary surfaces. But my concern is that, in the above case, all my physical surfaces that I created in Gmsh such as fixed boundary face, load boundary face and contact faces seems to be getting merged in Elmergui. This is making difficult to assign the physical constraints on the boundary faces such as giving
displacement 1=0, displacement 2=0,displacement 3=0 for fixed faces boundary;
normal force = -1e6 for load face boundary.
,which I have tradionally given in Elmergui before generating SIF file and running simulation.
Previously for single component models, boundary created in Gmsh were separate as shown below:

I have also attached google link for the mesh file of current case with 2 component :
https://drive.google.com/file/d/1HfkYSG ... sp=sharing

Thanks again

Re: Applying pressure on surfaces

Posted: 28 Jul 2023, 11:11
by kevinarden
Can you post the geo file? If you use physical groups to name volumes and surfaces, than the volumes become bodies in Elmer, and the named surfaces become individual boundaries.
Here is an example
test.geo
(538 Bytes) Downloaded 56 times

Re: Applying pressure on surfaces

Posted: 28 Jul 2023, 15:26
by ufifilters@123
I tried to create the geo file from the stp file I used for creating the mesh (.msh) file in Gmsh. I hope it is helpful.