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Contact Mechanics - Convergence in Large Deformations
Posted 10.02.2014, 05:12 GMT-5 3 Replies
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Hello,
I am trying to model the compression of a soft cell by a rigid indentor.
In the attached model, using Comsol's contact module and its default augmented Lagrangian method, I am able to obtain results for compressions up to 70%. However, the results are not smooth. Therefore, I would like to obtain convergence with a finer mesh and/or with a finer time step.
However, when I try either of these, the maximum compression I am able to obtain is 17%. Besides, for finer meshes, I observe some interpenetration of the indentor of the cell, which is not physically acceptable.
Does anyone of ideas on how to obtain a better convergence for large compressions?
Any help is appreciated.
Thank you,
Lionel
I am trying to model the compression of a soft cell by a rigid indentor.
In the attached model, using Comsol's contact module and its default augmented Lagrangian method, I am able to obtain results for compressions up to 70%. However, the results are not smooth. Therefore, I would like to obtain convergence with a finer mesh and/or with a finer time step.
However, when I try either of these, the maximum compression I am able to obtain is 17%. Besides, for finer meshes, I observe some interpenetration of the indentor of the cell, which is not physically acceptable.
Does anyone of ideas on how to obtain a better convergence for large compressions?
Any help is appreciated.
Thank you,
Lionel
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3 Replies Last Post 16.10.2016, 16:15 GMT-4
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Posted:
1 decade ago
Hi Lionel,
You can reach a much higher compression level if you switch to penalty contact and increase the penalty stiffness to 100 times the default value (easier done in version 4.4). At that level of deformation I would pay attention to the material model (Neo-Hookean) and whether it reasonably captures your material behavior at that level of strain.
Nagi Elabbasi
Veryst Engineering
You can reach a much higher compression level if you switch to penalty contact and increase the penalty stiffness to 100 times the default value (easier done in version 4.4). At that level of deformation I would pay attention to the material model (Neo-Hookean) and whether it reasonably captures your material behavior at that level of strain.
Nagi Elabbasi
Veryst Engineering
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Posted:
1 decade ago
Hello Nagi,
Thank you very much for your reply.
As I am working in v4.3b, I tried to implement the penalty method manually following the steps employed in the tutorial "snap_hook_penalty".
Unfortunately, I was not able to obtain convergence, even for first value of parameter (model attached).
Do you have any advice on how to proceed?
Best,
Lionel
Thank you very much for your reply.
As I am working in v4.3b, I tried to implement the penalty method manually following the steps employed in the tutorial "snap_hook_penalty".
Unfortunately, I was not able to obtain convergence, even for first value of parameter (model attached).
Do you have any advice on how to proceed?
Best,
Lionel
Attachments:
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Posted:
8 years ago
Hi Lionel,
I am experiencing the same exact issue with Mooney-Rivlin material model. Were you able to solve your problem?
Thanks
Kourosh
I am experiencing the same exact issue with Mooney-Rivlin material model. Were you able to solve your problem?
Thanks
Kourosh