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No penetration occurs at contacting boundaries
Posted Aug 8, 2014, 5:13 p.m. EDT 2 Replies
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Hi,
I've been reading through threads where others in the Forum have one material penetrating another at boundaries even when using contact pairs. What about the opposite where only deformation occurs when penetration is expected?
Does anyone have an idea why the HDPE needle does not penetrate the hyperelastic membrane? The model uses a prescribed displacement to bring the needle into contact with the membrane. With or without contact pairs, no penetration occurs.
Does anyone know why? Any help or comments are greatly appreciated.
Thanks,
Art
I've been reading through threads where others in the Forum have one material penetrating another at boundaries even when using contact pairs. What about the opposite where only deformation occurs when penetration is expected?
Does anyone have an idea why the HDPE needle does not penetrate the hyperelastic membrane? The model uses a prescribed displacement to bring the needle into contact with the membrane. With or without contact pairs, no penetration occurs.
Does anyone know why? Any help or comments are greatly appreciated.
Thanks,
Art
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2 Replies Last Post Aug 11, 2014, 12:51 p.m. EDT
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Posted:
10 years ago
Hi Art,
The tip of the needle is probably initially touching the membrane, and you end your model with a Union operation. That makes COMSOL assume they are bonded and share the same node. No penetration can occur then. Switch the final geometry operation form Union to Assembly.
Nagi Elabbasi
Veryst Engineering
The tip of the needle is probably initially touching the membrane, and you end your model with a Union operation. That makes COMSOL assume they are bonded and share the same node. No penetration can occur then. Switch the final geometry operation form Union to Assembly.
Nagi Elabbasi
Veryst Engineering
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Posted:
10 years ago
Hi Nagi,
Thanks for your response. It was not exactly straight forward to figure out how to form the assembly. I figured it out but am not exactly sure what I did.
After forming the assembly, the needle did begin to penetrate the membrane but only entered so far with the membrane continuing to deform; screenshot is attached.
At a displacement just under 2mm, COMSOL reported an error in convergence.
Do you think that the partial penetration is due to the model properties of the hyperelastic membrane? It is also some what surprising that there isn't a higher concentration of stress at the needle entry point.
Do you have any suggestions on eliminating the error and any comments regarding the needle penetration?
Thanks,
Art
Thanks for your response. It was not exactly straight forward to figure out how to form the assembly. I figured it out but am not exactly sure what I did.
After forming the assembly, the needle did begin to penetrate the membrane but only entered so far with the membrane continuing to deform; screenshot is attached.
At a displacement just under 2mm, COMSOL reported an error in convergence.
Do you think that the partial penetration is due to the model properties of the hyperelastic membrane? It is also some what surprising that there isn't a higher concentration of stress at the needle entry point.
Do you have any suggestions on eliminating the error and any comments regarding the needle penetration?
Thanks,
Art
Attachments: