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## #1 2021-08-31 12:20:02

remrider
Member
Registered: 2021-08-30
Posts: 4

### Convergence issue due to contact

Hi everyone,

I'm beginning with Code Aster and I'm now working on the simulation of a clutch release bearing. This simulation involves contact that I consider frictionless. An axial force will be applied to then calculate the deformation and stress in the inner and outer rings.

My model is composed of 5 parts :
- a circular plate in contact with the outer ring where the pressure will be applied
- the outer ring
- the ball
- the inner ring
- another circular plate in contact with the inner ring that will be encastered

My boundary conditions are :
- load pressure on the first circular plate, applied with a step function
- encastered conditions for the second plate
- symmetry conditions for the inner and outer rings

Here are my different concerns about the model :

1) Is my mesh suitable for this king of study ? I have read that for this kind of contact with curved surfaces, the mesh size has to be sufficiently fine in the contact zone. Do you think that my mesh is ok ?

2) My second concern is about the contact itself. I have chosen a continuous formulation. For what I understood, in a continuous formulation, the structure can be held by contact itself. I'm I right on this point ? Are my options correct concerning contact ? When I'm lauching the calculation I get a message "the matrix of the system is singular". Do I have then to add other boundary conditions ? If yes which one ?

3) When CONTACT_INIT is set to INTERPENETRE, it seems that the contact is never recognize. That's why I decided to set it to Yes to "activate" the contact. Is it normal that the contact is not activated when the first option is chosen ?

4) My last problem is about the options of the non linear analysis. As mentioned in the documentation, I used DEFI_LIST_INST to have a smaller time step when needed. Are all the options for the non linear analysis correct ?

Thank you for your help because I'm struggling for days with this calculation and I felt a bit hopeless

Best regards.

Remy

PS : you can find below the command file. The size of the hdf file is too big, if needed, just let me know

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## #2 2021-08-31 12:24:02

remrider
Member
Registered: 2021-08-30
Posts: 4

### Re: Convergence issue due to contact

Here a photo of my geometry + mesh

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## #3 2021-08-31 13:36:34

sameer21101970
Banned
Registered: 2019-09-06
Posts: 354

send med file

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## #4 2021-08-31 15:41:26

remrider
Member
Registered: 2021-08-30
Posts: 4

### Re: Convergence issue due to contact

The size is too big I can't put it here even with a .zip file. Maybe I can send it to you directly

Last edited by remrider (2021-08-31 15:47:23)

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## #5 2021-09-01 07:36:46

sameer21101970
Banned
Registered: 2019-09-06
Posts: 354

### Re: Convergence issue due to contact

Ok
you can directly sameer21101970@gmail.com .

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## #6 2021-09-06 09:15:23

sameer21101970
Banned
Registered: 2019-09-06
Posts: 354

### Re: Convergence issue due to contact

Kindly email, all volumes mesh seperately as need to re-mesh all components.

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