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Pressure transmission between microdomes that are tangent to one another

Posted 25.05.2020, 02:46 GMT-4 Structural & Acoustics, Structural Mechanics Version 5.1 1 Reply

Valerie Tan
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Hello! I've encountered some problems with pressure transmission between microdomes that are tangent to one another. There seems to be a problem with the meshing at the contact points. I've tried form assembly and contact pair generation but the solution will not converge. The details of my problem are summarised in this google site: https://sites.google.com/view/comsol-troubleshooting/home?authuser=2

1 Reply Last Post 25.05.2020, 15:22 GMT-4
Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 25.05.2020, 15:22 GMT-4

Hi,

This was one of the most comprehensive formulations of a forum question I have seen. If everyone did like this, the number of answered questions would probably increase tremendously. :-)

I cannot really tell what is going on, but have some quick remarks:

  1. In contact problems, you can only use Form Union if the contact boundaries are disjoint in the initial configuration. If they touch, they will be ‘welded’ in the common areas unless you use Form Assembly.
  2. If possible, use displacement control on the upper surface, and use the reaction forces to evaluate the thus applied load. If not, you will probably need some extra conditions for keeping the upper part stable during the first load steps. Easiest it to add weak spring
  3. A plot of the stress in the vertical direction would probably help debugging.
  4. Plots of the contact pressure and gap will also help.
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Henrik Sönnerlind
COMSOL
Hi, This was one of the most comprehensive formulations of a forum question I have seen. If everyone did like this, the number of answered questions would probably increase tremendously. :-) I cannot really tell what is going on, but have some quick remarks: 1. In contact problems, you can only use Form Union if the contact boundaries are disjoint in the initial configuration. If they touch, they will be ‘welded’ in the common areas unless you use Form Assembly. 2. If possible, use displacement control on the upper surface, and use the reaction forces to evaluate the thus applied load. If not, you will probably need some extra conditions for keeping the upper part stable during the first load steps. Easiest it to add weak spring 3. A plot of the stress in the vertical direction would probably help debugging. 4. Plots of the contact pressure and gap will also help.

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