Dear Yves, Thank you for your reply, thanks to which I’ve started studying the tutorials, and I’ve a question related to the Thermo-elastic and electrical coupling example.
Looking at the python file I can read that the convection coefficient D is applied to all the surfaces except the holes and the left surface (in my opinion it is not applied to the right surface too, can you confirm?). Then I see that Fourier_Robin_brick and source_term_brick are used to impose the convection condition the Top and Bottom edges. I suppose that the equation to be included is something like q” = D*(Tair-T) = k*grad(T).n => grad(T).n + D/k*T = D/k*Tair The left side term is supposed to be assembled via the Fourier_Robin_brick whereas the right side term via the source_term_brick. Questions: 1) Looking at the python file I see that you calculate D/epsilon and D*Tamb/epsilon where epsilon is the plate thickness. Is this an error and we should replace epsilon with k? 2) Does the Fourier_Robin_brick work only on the stiffness matrix? I’m asking because the usage of these bricks, their convection equations and relevant assembly, are not mentioned/explained in the tutorial. Thank you very much. Lorenzo > Il giorno 20 apr 2021, alle ore 11:02, Yves Renard <[email protected]> > ha scritto: > > > Dear Lorenzo, > > Through its Python interface, GetFEM offers generic tools for complex > modeling and evolutionary equations, even non-linear ones, can be taken into > account using the weak form language (GWFL). Practical tools for managing > meshes, regions in these meshes, meshes cut by level-sets complete the > system, as well as post-processing functions. These tools allow to build > complex static or transient codes, but of course, GetFEM is above all a > toolbox, not a ready-made code allowing to do simulations quickly. > > Examples are given in the interface/src/python directory on basic modeling. > In particular, it may be interesting to follow the tutorial example > http://getfem.org/tutorial/index.html on the thermo-elastic problem. > > Best regards, > > Yves > > > > On 19/04/2021 18:48, Lorenzo Ferro wrote: >> Dear All, >> >> I need to simulate a flash-butt welding process, where two steel bars are >> welded together, head to head, applying electrical current (flash welding) >> until the bar heads reach the melting temperature, eventually pushing them >> together to make the joint. >> During this process, some metal reaches the melting point (almost >> evaporation) and bursts away, so some metal is lost during the heating phase >> and the two bars must be brought closer together to keep the current flowing >> and the process going on. >> >> So the model would include (at least): >> A) a transient thermal simulation with external convection and radiation >> B) internal heat generated by joule effect >> C) non-linear material properties >> D) elements removal from the simulation once the melting temperature has >> been reached, with consequent change of boundary elements on the heads of >> the bars >> E) moving the bars closer, step-by-step, to restore the surface contact and >> current flow (no need of a real contact function, contact can be estimated >> based on the boundary elements distance, since some current can flow also >> when the faces are enough close). >> >> To do so I've two options: >> 1) making a simulation model with a programming language like Python, etc... >> 2) exploring the usage of the GetFEM library. At the end of the work, a new >> scientific article will follow. The simulation is only the first part, the >> article will also include a part related to the automation control of the >> welding process. >> >> Questions: >> i) can GetFEM be convenient for the implementation of the above mentioned >> problem? >> ii) does GetFEM allows to implement all of the above features? >> iii) principally, can you give me guidance about the needed GetFEM native >> functions? >> >> I've never used GetFEM before but I'd like to learn how to use it, also in >> view of other future projects and publications. >> >> Thank you in advance. >> Lorenzo > > > -- > > Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 > INSA-Lyon > 20, rue Albert Einstein > 69621 Villeurbanne Cedex, FRANCE > http://math.univ-lyon1.fr/~renard > > --------- >
