Meshing problems


#1

Hey guys,

I wanted to do a simulation of a gear pair but already failed at the meshing part.

The log says:

Searching Naming Service + found in 0.1 seconds
===========================================================
Logger server: put log to the file:
===========================================================
Searching Logger in Naming Service ++++++ found in 3.0 seconds
Searching /Registry in Naming Service + found in 0.5 seconds
Searching /Kernel/ModulCatalog in Naming Service +Warning: this sequence type (GEOM/ShapeError,GEOM/ShapeErrors) has unknown content type, it will be ignored.
found in 0.5 seconds
RunStudy
Searching /myStudyManager in Naming Service +++++ found in 2.5 seconds
Searching /Containers//FactoryServer in Naming Service +Report : 1 unknown entities.
DEBUG:Thread-1:RELEASE PORT (2810)
DEBUG:Thread-1:read configuration file
DEBUG:Thread-1:load busy_ports: []
DEBUG:Thread-1:write busy_ports: []
DEBUG:Thread-1:released port port: 2810
found in 0.5 seconds
Start SALOME, elapsed time : 10.9 seconds
createNewStudy
extStudy 1
addToStudy() failed
Terminating SALOME on port 2810...

These are my settings:

Anybody has an idea how I can do a better mesh -or first- solve this problem? :smile:

Thank you very much. I will keep trying!


#2

Update: Still was not able to mesh my geometry. Also tried Tetrahed. with refinements in the area of contact. Failed meshing again.

Feel free to jump in :smile:

Cheers!


#3

@jousefm,

mhm - did the operations log (not the meshing log) say anything?

Best,

David


#4

Hi @dheiny,
as I see nothing if you mean picture number 1 (Mesh Operation Event Log).


#5

Mhm - very odd. Any chance you could provide me with the CAD model?


#6

Good evening @dheiny,

I will send you a private message.


#7

@jousefm, thanks! Will look into it!


#8

Hi @dheiny,

any tips for my model?


#9

Hi @jousefm,

sorry for the delayed answer - unfortunately I didn’t have the time to look into it yet, but @ahmedhussain18 will now have a look!

Best,

David


#10

Hello @jousefm,

I had a close look at the problem. It is obviously related to some Meta-data that comes with your step model, storing some presentation information (like visibility) and I think also material data, that can not be imported properly by our mesher. We are looking into this right now in order to fix that for future cases. Can you tell me which software has been used to export that model.

In the meantime should I share you a project with the cleaned-up geometry or send you the file, so that you can proceed with your work?

Thx for reporting that Jousef!

All the best

Alex


#11

Good evening Alex!

I have to look that up. At that time I had to many CAD programs running on my laptop. As soon as I know it, I will let you know what program I used.

Would be awesome if you could send it to me. I will make it public anyway after simulating it.

Cheers mate and thanks for looking into it, really appreciate that!

Jousef


#12

@afischer

Spaceclaim was the program I used to export. Export as Parasolid or as in my case STEP


#13

Hey Jousef, that’s good news, as we use SpaceClaim a lot and normally this problem does not occur ;-). We will test with SpaceClaim, but it looks like we already have a stable fix.

Best Alex


#14

Hey guys,

managed to set my project so far.
I did a mistake I guess. I want that typical “pitting” shear stress under the surface where the contact is. Did I anything wrong concerning the master-slave-assignment?

Would be awesome if you could take a look at it :smile:

https://platform.simscale.com/?publiclink=315074f6-f131-4800-828d-764b9e47151a

Thanks and cheers guys!


#15

Hi @jousefm,
generally it looks very good, well done!
Just two changes:

  1. You have to provide the correct center for the rotation and the moment application. I changed the two gears such that I apply the rot+moment on the one centered at 0.
  2. I changed the remote displacement behavior to “rigid” to not have the gear deforming since its pretty thin.

And some general remarks:

  • The remote boundary conditions are generally only valid for small rotations, for big rotations the may suffer from unphysical expansion effects.
  • The mesh in your contact region is very coarse, you need a very fine surface mesh to represent the contact stresses correctly
  • Beware the time stepping. You ramped the moment with 20*t, but your time stepping reaches only 0.01, so your final moment will be 0.2 Nm.

Here is the link to the project with the above mentioned changes:
https://platform.simscale.com/?publiclink=522b046e-ebf1-438b-82f4-3824614e6e49

Best,
Richard


#16

Hi @rszoeke ,

yes I supposed that was my mistake! Did not apply my momentum in the center of my gear.

Refering to your general remarks:

  1. Is there a possibility to overcome this effects with any settings in the solver?
  2. That is true. But I always see if it runs first, then do a finer mesh. Time is money :-]
  3. You are totally right!

Thank you very much @rszoeke! Appreciate your help :smile:

Have a nice weekend everybody!


#17

Hi @jousefm,

that’s a good approach, always start with a coarse model first!
Concerning the remote force and large rotations, it’s currently not possible.
If you have a prescribed rotation+displacement, use the “rotating motion” constraint, this works then like the remote constraint with undeformable option, but also allows large rotations and you can also move the center of rotation with time.

Good luck with your project!

Best,
Richard