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COMSOL Capabilities for 3D Large Deformation Elasto-Plastic Modeling

Posted 24 set 2010, 12:03 GMT-4 Structural Mechanics Version 3.5a 4 Replies

Kay Furman
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Is COMSOL capable of contact modeling with self-intersections?

We are trying to model 3D contact under large deformations - where the geometry collapses and comes into contact with itself.

We have tried two beam models that contact perpendicularly and have been unable to optimize contact pressure, offset, penalty factor, contact/identity pairs, and manual scaling factors. In the failed and solved solutions, the geometry appears to have penetrated itself. The solution only converges with a proper solution when the beams are in initial contact, using identity and contact pairs.

Is contact modeling in COMSOL capable of convergence for large deformation models while respecting internal boundaries?
4 Replies Last Post 14 apr 2011, 11:18 GMT-4
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Hello Kay Furman

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Yajuan Liu
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Posted: 1 decade ago 13 apr 2011, 22:59 GMT-4
Hello Kay!

I don't know much about of self-intersections. Isn't your model an assembly? I am working on a 3D contact model, and there is no internal boundary in my model.

My problem has no convergence until now. Could you give me some advice? which method did you use, the augmented method or penalty method? How did you set to make the beams in initial contact? Could you give me more details about it?

Any advice will be helpful and appreciated! Thank you in advance!

Best wishes!

Yajuan
Hello Kay! I don't know much about of self-intersections. Isn't your model an assembly? I am working on a 3D contact model, and there is no internal boundary in my model. My problem has no convergence until now. Could you give me some advice? which method did you use, the augmented method or penalty method? How did you set to make the beams in initial contact? Could you give me more details about it? Any advice will be helpful and appreciated! Thank you in advance! Best wishes! Yajuan
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 14 apr 2011, 01:09 GMT-4
Hi

contact issues are tricky, particularly you need to check the scaling of the variables, in particular the contact pressure as these often get 1E6-1E9 times larger during the process, and that is about the useful range of double precision binary numbers !

It is a question of tweaking and learning, I cannot give many further ideas. Self contact or separate contact is not an issue

I have posted one simple example on another thread look for "Contact41tstik_1.mph" but its for 4.1 sorry not using my 3.5 any longer

--
Good luck
Ivar
Hi contact issues are tricky, particularly you need to check the scaling of the variables, in particular the contact pressure as these often get 1E6-1E9 times larger during the process, and that is about the useful range of double precision binary numbers ! It is a question of tweaking and learning, I cannot give many further ideas. Self contact or separate contact is not an issue I have posted one simple example on another thread look for "Contact41tstik_1.mph" but its for 4.1 sorry not using my 3.5 any longer -- Good luck Ivar
Kay Furman
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Posted: 1 decade ago 14 apr 2011, 08:51 GMT-4
Hello All,

Thanks very much for your insights... it's been some months since my initial post and I actually discovered that COMSOL 3.5 was not able to solve the contact problem as I was intending.

I believe it was an issue with the solver being unable to handle both parametric, large deformation analysis and adaptive mesh refinement. I spent some time looking back in my notes, but unfortunately no longer have the reference to where I found this in the multiple help guides.

If it helps, I have since had great (and much more straightforward) success with ABAQUS 10.

Hope that helps!
Kay
Hello All, Thanks very much for your insights... it's been some months since my initial post and I actually discovered that COMSOL 3.5 was not able to solve the contact problem as I was intending. I believe it was an issue with the solver being unable to handle both parametric, large deformation analysis and adaptive mesh refinement. I spent some time looking back in my notes, but unfortunately no longer have the reference to where I found this in the multiple help guides. If it helps, I have since had great (and much more straightforward) success with ABAQUS 10. Hope that helps! Kay
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 14 apr 2011, 11:18 GMT-4
Hi

No that does not help ;) I have COMSOL not A...

but so far my contact issues in v4.1 are all solving, so I'm happy

--
Good luck
Ivar
Hi No that does not help ;) I have COMSOL not A... but so far my contact issues in v4.1 are all solving, so I'm happy -- Good luck Ivar

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