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Rigid Connectors
Posted Nov 24, 2010, 9:28 a.m. EST 1 Reply
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I am trying to verify the Eigenfrequency analysis in COMSOL. I am comparing a rectangular plate to the solution found by Meirovitch in Analytical Methods in Vibrations. The author has only solved for a rectangular plate that is a simply supported plate. I have tried many different boundary conditions but the one that seems to stick out is the Rigid Connector boundary condition.
The plate does have a thickness to it and I have put the rigid connector constraint along the thickness boundary. When I run the model, it tells me that there are void matrices at the origin (0,0,0). Reading the COMSOL literature,it seems the Rigid Connector BC is what I need in that it allows no displacement yet does not restrict rotation.
The plate does have a thickness to it and I have put the rigid connector constraint along the thickness boundary. When I run the model, it tells me that there are void matrices at the origin (0,0,0). Reading the COMSOL literature,it seems the Rigid Connector BC is what I need in that it allows no displacement yet does not restrict rotation.
1 Reply Last Post Nov 24, 2010, 9:58 a.m. EST
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Posted:
1 decade ago
Hi
The RBC is new in V4 (and very handy) but I'm still struggling to really understand all its implications.
As you say it maked the boundary fully rigid, what you could do before with a few equations: see the 3.5a edge rigidification example in the doc.
But I'm not fully confident on all the bahaviours among other in eigenfrequency mode, in static I use it as large angle rotation metrology operator, as imposed moment, force or prescripted displacements operator, provided that the rigid link on the boundary is OK (often NOT the case, so I'm expecting once a new "soft Body connector")
The angles are great, as they are solved via quaternions and accept large displacements without singularities, what the traditional "small angle" curl of displacement field operator is not giving me
--
Good luck
Ivar
The RBC is new in V4 (and very handy) but I'm still struggling to really understand all its implications.
As you say it maked the boundary fully rigid, what you could do before with a few equations: see the 3.5a edge rigidification example in the doc.
But I'm not fully confident on all the bahaviours among other in eigenfrequency mode, in static I use it as large angle rotation metrology operator, as imposed moment, force or prescripted displacements operator, provided that the rigid link on the boundary is OK (often NOT the case, so I'm expecting once a new "soft Body connector")
The angles are great, as they are solved via quaternions and accept large displacements without singularities, what the traditional "small angle" curl of displacement field operator is not giving me
--
Good luck
Ivar