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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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Contact Modeling in Stationary a Study

Posted 2014年7月30日 GMT-4 16:25 Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers, Structural Mechanics Version 4.4 3 Replies

Rachel Foreman
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I am trying to create a simulation of two layers of hyperelastic material (a dense polymer and a foam layer) under compression. The layers are not bonded together, but they are in contact. Both materials are represented by Ogden hyperelastic constitutive model. The displacement discretization is set to 'quadratic'. I am not getting convergence when I am using contact (it works without the contact). Any advice (maybe regarding solver or component/physics settings to tinker with?) is greatly appreciated.
3 Replies Last Post 2014年7月31日 GMT-4 17:46
Josh Thomas Certified Consultant
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Posted: 1 decade ago 2014年7月30日 GMT-4 16:34
Rachel-

Without looking at your mph file, but just considering the text of your post here are a couple things:

1) Instead of solving for the full load/displacement in one shot, use a parametric approach that incrementally ramps up the loading/displacement. This helps a lot with convergence and gives physical intermediate results up to the point of convergence failure.

2) Use linear element discretization for better contact convergence.

--
Best regards,
Josh Thomas
AltaSim Technologies
Rachel- Without looking at your mph file, but just considering the text of your post here are a couple things: 1) Instead of solving for the full load/displacement in one shot, use a parametric approach that incrementally ramps up the loading/displacement. This helps a lot with convergence and gives physical intermediate results up to the point of convergence failure. 2) Use linear element discretization for better contact convergence. -- Best regards, Josh Thomas AltaSim Technologies
Rachel Foreman
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Posted: 1 decade ago 2014年7月31日 GMT-4 17:28
Thanks for your input, Josh. I tried your suggestions, but still no convergence. Any other ideas?
Thanks for your input, Josh. I tried your suggestions, but still no convergence. Any other ideas?
Josh Thomas Certified Consultant
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Posted: 1 decade ago 2014年7月31日 GMT-4 17:46
I would try doing a displacement controlled rather than a load controlled problem. I don't believe all of your rigid body modes for the separate bodies are being restrained properly. Also, I would recommend solving using a linear elastic material model for both parts and troubleshooting the contact problem. Then, add in the non-linear material model.

Adding one non-linearity at a time is good practice!

--
Best regards,
Josh Thomas
AltaSim Technologies
I would try doing a displacement controlled rather than a load controlled problem. I don't believe all of your rigid body modes for the separate bodies are being restrained properly. Also, I would recommend solving using a linear elastic material model for both parts and troubleshooting the contact problem. Then, add in the non-linear material model. Adding one non-linearity at a time is good practice! -- Best regards, Josh Thomas AltaSim Technologies

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