Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
Apr 25, 2011, 4:10 a.m. EDT
Hi
if you two plates are in contact (common boundary, and you use the default "union" geometry "Finish" mode, then you have by default "continuity of the displacements between both items.
Rigid Connector is a tricky one, be sure you really understand what it's doing, it's not only adding nice BC possibilities such as torque/moment loads but it also makes the Boundary fully stiff, that is not always the desired effect
Another issue, try to avoid Point and Edge loads in 3D, as these re singularities and destroy the useful stress analysis and use only distributed loads (Domain = volume i.e. gravity or volume forces or Boundary = surfaces loads i.e. distributed pressure or total Force => pressure = average force/Area applied
But you might want to do a periodic (or anti-periodic link, from what I suspect of your model), then I would rather use pairs, or coupling variables, check the doc
Finally, an advice, update to latest patch (# 3 by today) as there are a few internal formula issues in the old one you use
--
Good luck
Ivar
Hi
if you two plates are in contact (common boundary, and you use the default "union" geometry "Finish" mode, then you have by default "continuity of the displacements between both items.
Rigid Connector is a tricky one, be sure you really understand what it's doing, it's not only adding nice BC possibilities such as torque/moment loads but it also makes the Boundary fully stiff, that is not always the desired effect
Another issue, try to avoid Point and Edge loads in 3D, as these re singularities and destroy the useful stress analysis and use only distributed loads (Domain = volume i.e. gravity or volume forces or Boundary = surfaces loads i.e. distributed pressure or total Force => pressure = average force/Area applied
But you might want to do a periodic (or anti-periodic link, from what I suspect of your model), then I would rather use pairs, or coupling variables, check the doc
Finally, an advice, update to latest patch (# 3 by today) as there are a few internal formula issues in the old one you use
--
Good luck
Ivar
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Posted:
1 decade ago
Apr 25, 2011, 5:08 p.m. EDT
Thanks for the response.
I use the the Rigid Connector because I want to restrict the motion of the plates along certain axes (x,y) but not the z axis. Is there a way I can do this without using the RC?
Thanks for the response.
I use the the Rigid Connector because I want to restrict the motion of the plates along certain axes (x,y) but not the z axis. Is there a way I can do this without using the RC?
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Apr 25, 2011, 5:22 p.m. EDT
Hi
yes the prescribed displacement is there for that, one of the nice things with the RBC is the access to the rotation angle in a quaternion formulation hence, also valid for large angles
--
Good luck
Ivar
Hi
yes the prescribed displacement is there for that, one of the nice things with the RBC is the access to the rotation angle in a quaternion formulation hence, also valid for large angles
--
Good luck
Ivar
Nagi Elabbasi
Facebook Reality Labs
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Posted:
1 decade ago
Apr 25, 2011, 11:46 p.m. EDT
You can “fuse” two surfaces such that their displacement is the same in X, Y but not Z, by defining a Boundary Similarity Model Coupling. Define one surface as the Source and the other surface as the Destination. If we call this coupling operator bndsim1, then you add a prescribed displacement on the Destination surface with u=bndsim1(u), v=bndsim1(v), and leave the Z direction free.
Nagi Elabbasi
Veryst Engineering
You can “fuse” two surfaces such that their displacement is the same in X, Y but not Z, by defining a Boundary Similarity Model Coupling. Define one surface as the Source and the other surface as the Destination. If we call this coupling operator bndsim1, then you add a prescribed displacement on the Destination surface with u=bndsim1(u), v=bndsim1(v), and leave the Z direction free.
Nagi Elabbasi
Veryst Engineering