Thank you very much for your answer. So I have to make the simulation on the whole model (8/8) ? But then the cost of the simulation will be 8 times more ? And thus, I do not take benefit of the symmetry of the problem, or I misunderstood something ?
Thank you 2013/2/6 Rui Maciel <[email protected]> > > > On 02/05/2013 03:51 PM, Adrien Girard wrote: > >> Hello, >> >> I just finish university and I am now working as a mechanical engineer and >> I am still confused with some points of FEM theory. >> >> I have to make the complete thermal analysis of a rectangular box, I >> decided to use the symetry of the problem and thus modelise only 1/8 of >> the >> box. But now, I wonder when I have to add the symetry to the problem. >> >> - 1) to the mechanical model ? (before the simulation) >> - 2) at the simulation phase ? >> - 3) only for the post process, to visualise the result ? >> > > It's the 1st one: before the simulation. > > The main point of taking advantage of a model's symmetry is to cut down > the computational costs of getting a solution to the problem it describes. > In your example, if you only analyze 1/8th of a thermal model then it will > have approximately 1/8th of the degrees of freedom that it would otherwise > require. Considering that the computational complexity of the algorithms > which dominate the whole computational process, as it tends to lie > somewhere between either O(n^2) or O(n^3), (n) being the number of degrees > of freedom, you can get an idea of how much more efficient the whole > process becomes. > > Taking advantage of a model's symmetry can also eases the computational > requirements of the whole visualization process, but in general, when > compared with the previous point, this detail is pretty much a non-issue. > There are plenty of ways to skin this proverbial cat, and symmetry doesn't > tend to come up in the conversation. > > > Hope this helps, > Rui Maciel > > ______________________________**_________________ > gmsh mailing list > [email protected] > http://www.geuz.org/mailman/**listinfo/gmsh<http://www.geuz.org/mailman/listinfo/gmsh> > -- Adrien Girard GSM : 0031 615 355 049
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