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Difference between Beam and Solid Mechanics Physics

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Hi,

I just want to know if there's a punctual difference between using the Physics in question when performing a 2D cantilever beam analysis for a CNT switch, which I'm modeling. I mean, which of the two Physics would suit better for solving my problem? I already used Solid Mechanics for characterizing the switch at stationary mode, but now I want to incorporate time-dependant analysis, so I was thinking about remaking the model but using Beam Physics, just for curiosity; so If anyone of you can summarize the pros and cons of each Physic, I'd be very grateful.

Regards

1 Reply Last Post Jan 24, 2011, 6:10 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Jan 24, 2011, 6:10 p.m. EST
Hi

there are not that many differences, I find. 3D solid is somewhat cleaner, with less to input but requires far finer mesh and higher number of elements, hence far more time to solve. You have only u,v,w the three displacements, no rotations by default.

The beam models are simpler, you need some more info as beam parameters, and have to play a little with local coordinates transforms. But the model has far fewer mesh elements, hence solves 10-100 times quicker for rougly the same results. Furthermore, you have access to the rotations, in addition to the u,v,w displacements.

Coupling physics can be more tedious, a FSI physics is set up for solid, not for beams

Good exercice anyhow, and i.e. for large slender steel structures it's far easier to handle them as beams than as ful 3D models

--
Good luck
Ivar
Hi there are not that many differences, I find. 3D solid is somewhat cleaner, with less to input but requires far finer mesh and higher number of elements, hence far more time to solve. You have only u,v,w the three displacements, no rotations by default. The beam models are simpler, you need some more info as beam parameters, and have to play a little with local coordinates transforms. But the model has far fewer mesh elements, hence solves 10-100 times quicker for rougly the same results. Furthermore, you have access to the rotations, in addition to the u,v,w displacements. Coupling physics can be more tedious, a FSI physics is set up for solid, not for beams Good exercice anyhow, and i.e. for large slender steel structures it's far easier to handle them as beams than as ful 3D models -- Good luck Ivar

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