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Difference between `Total stress` and `Viscous stress`?

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Hi,
I want to calculate the force required to move the bottom sheet, in the attached problem. should I use `total stress` for the line integration or `vsicous stress`?

Thanks,
Maryam


1 Reply Last Post 20 mars 2015, 03:06 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago 20 mars 2015, 03:06 UTC−4
Hi

My way is to open the "equation view" (you might have to set in in your "File Preferences" settings) and study what is behind the values used by COMSOL.
I'm not by my workstation now, but the viscous stress is from my understanding the one in the viscoelastic material alone, while the total stress might also add in some from the structure or "solid" part.

To test out: look at the two, make a cut line just above and just below the interface boundary and see which one they look closest to

I do many of these simple test/model analysis or V&V activities when I construct a model as I do not manage to remember exactly the definition of all the internal COMSOl variables I suspect there are more than 10'000 if you combine all physics ;)

--
Good luck
Ivar
Hi My way is to open the "equation view" (you might have to set in in your "File Preferences" settings) and study what is behind the values used by COMSOL. I'm not by my workstation now, but the viscous stress is from my understanding the one in the viscoelastic material alone, while the total stress might also add in some from the structure or "solid" part. To test out: look at the two, make a cut line just above and just below the interface boundary and see which one they look closest to I do many of these simple test/model analysis or V&V activities when I construct a model as I do not manage to remember exactly the definition of all the internal COMSOl variables I suspect there are more than 10'000 if you combine all physics ;) -- Good luck Ivar

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