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How to make sure AC/DC and Structural models are coupled? SIMULATION ATTACHED

Posted 20 mars 2013, 11:00 UTC−4 Low-Frequency Electromagnetics, Mesh, Studies & Solvers, Structural Mechanics Version 4.3a 3 Replies

Dan Jia
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I'm doing my thesis on the magneto-mechanical coupled analysis. The attached file is only a simple example showing what I want to do about magneto-mechanical coupling. I chose to use the AC/DC model, ALE, Structural mechanics model. In the model, there are a permanent magnet and a steel rod. One end of the rod is fixed, while the other is free. The magnet will draw the rod and cause deflection of the steel rod. Once the steel rod deflects, it goes nearly to the magnet, which cause a increment of magnetic force. The magnetic force will then make the rod's deflection greater.

My concern are as follows:
1. I use 'segregated' in the stationary solver. When I run the simulation, an 'error vs. iteration' plot always come out, which includes three lines. What's the meaning of those lines? Are they converging lines?

2. Though I've arranged the ALE, AC/DC, structural mechanics as the 1st, 2nd and 3rd segregated group to be solved. I'm not sure if they have been coupled. Does COMSOL do automatically coupling?

3. If my model in the attached file is a successful coupled model, how can I make sure the results have converged? How can I show the magnetic force is increasing vs. iterations? Do I need to store the results?

THANKS VERY MUCH.:)
3 Replies Last Post 20 mars 2013, 17:47 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 20 mars 2013, 15:59 UTC−4
Hi

start to move the ALE above the solid, as for the sold part ALE does not apply, as solid has already the frame approach that does the work of an ALE then drive the ALE boundary to the solid by the u,v,w displacement of the solid

I would propose that your delete your solver sequence (this will also clear your Results section, or duplicate it so you need to re-order that afterwards. Then chose the default arrangement for the solver with the ALE node first or at best second, but before Solid

--
Good luck
Ivar
Hi start to move the ALE above the solid, as for the sold part ALE does not apply, as solid has already the frame approach that does the work of an ALE then drive the ALE boundary to the solid by the u,v,w displacement of the solid I would propose that your delete your solver sequence (this will also clear your Results section, or duplicate it so you need to re-order that afterwards. Then chose the default arrangement for the solver with the ALE node first or at best second, but before Solid -- Good luck Ivar
Dan Jia
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Posted: 1 decade ago 20 mars 2013, 16:22 UTC−4
Hi Ivar,

Thanks. Yet in the attached model, I've already set the segreated group in the following order: 1st is ALE, 2nd is AC/DC module, 3rd is Structural mechanics module. I can get the result. The results are converged.

My concern is does COMSOL do automatically coupling when I set the solver like this? Even if I did not use the fully coupled solver.

Furthermore, I wonder how I can know the relation between the deformation of steel rod versus the iteration. In each ineration, it has a certain displacement. I'm afraid the final contour plot of displacement only shows the displacement between the last two iterations, not the total displacement.

Thanks.
Hi Ivar, Thanks. Yet in the attached model, I've already set the segreated group in the following order: 1st is ALE, 2nd is AC/DC module, 3rd is Structural mechanics module. I can get the result. The results are converged. My concern is does COMSOL do automatically coupling when I set the solver like this? Even if I did not use the fully coupled solver. Furthermore, I wonder how I can know the relation between the deformation of steel rod versus the iteration. In each ineration, it has a certain displacement. I'm afraid the final contour plot of displacement only shows the displacement between the last two iterations, not the total displacement. Thanks.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 20 mars 2013, 17:47 UTC−4
Hi
nothing is really automatic ;) when you have several physics you need to add the correspoding BC nodes inthe different physics, as COMSOl cannot guess what you do want to do, but if you calculate the forces in ACDC, then in a solid below, COMSOl will propose as boundary forces user defined formulas, or to couple to the ACDC Force variable "automatically" but you must check all couplings manually one y one, tht these are linked as desired ;)

--
Good luck
Ivar
Hi nothing is really automatic ;) when you have several physics you need to add the correspoding BC nodes inthe different physics, as COMSOl cannot guess what you do want to do, but if you calculate the forces in ACDC, then in a solid below, COMSOl will propose as boundary forces user defined formulas, or to couple to the ACDC Force variable "automatically" but you must check all couplings manually one y one, tht these are linked as desired ;) -- Good luck Ivar

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