The figures got stripped by the mailing list. But rather than sending figures, I suggest you send over a simple example that I can run myself (as I said, systems_of_equations_ex6 could be a good starting point for that).
David On 03/04/2014 11:24 PM, Dafang Wang wrote: > Hi David, The two attached figures show the simulation of pressing an > incompressible cube. A constant pressure was applied uniformly on the > side y=y_min. Its opposite side, y=y_max, is the Dirichlet BC side, > which is fixed in the y and z directions. That is, this side deforms > only along the x axis. Both figures confirm this. The yellow frame > depicts the undeformed object, whereas the colored cube depicts the > deformed object. What is odd are two things: > > 1. I ran the same simulation code with a debug version of Libmesh and a > release version, respectively. However, as the two figures show, the > results are different: With the debug mode, the Dirichlet boundary > side (y=y_max) is stretched toward the positive-x direction; With > the release mode, this side is stretched toward the negative-x > direction. > 2. The Dirichlet boundary side (y=y_max) is supposed to deform evenly > along both directions of the x-axis. However, in both figures, the > deformation occurs mainly in one direction. > Thanks very much for your help. Cheers, Dafang Date: Tue, 4 Mar 2014 > 18:47:51 -0500 From: David Knezevic <[email protected]> > Subject: Re: [Libmesh-users] Dirichlet Boundary Condition on Part of > the Variables To: <[email protected]> Message-ID: > <[email protected]> Content-Type: text/plain; > charset="ISO-8859-1"; format=flowed Hi Dafang, I've done this a lot > for elasticity problems, and haven't had any problems with it. If you > can send through an example that illustrates what is happening (e.g. a > modified version of systems_of_equations_ex6), I'd be happy to have a > look. David On 03/04/2014 06:08 PM, Dafang Wang wrote: > >> Hi, >> >> The Libmesh Examples tell how to use the DirichletBoundary class to >> constrain all the variables in a system, but I am not sure how to apply >> zero Dirichlet BC to PART of the field variables in a system. I am >> solving a simple 3D elastic problem and I want to fix a boundary in the >> y direction while allowing it to move in the x-z plane. >> >> I did the following way but the results did not seem correct: >> My system has 3 displacement variables: ux (id=0), uy (id=1), >> and uz >> (id=2). >> std::vector<int> variables(1); >> variables[0] = uy; //the vector contains uy only >> DirichletBoundary bc(boundary_ids, variables, &ZeroFunction); >> >> The result I got showed that ux and uz were somewhat fixed with respect >> to one edge on the Dirichlet boundary side, which made no sense since ux >> and uz are supposed to evenly spread. >> >> Any suggestions will be greatly appreciated. >> >> Cheers, >> Dafang >> >> >> ------------------------------------------------------------------------------ >> Subversion Kills Productivity. Get off Subversion & Make the Move to >> Perforce. >> With Perforce, you get hassle-free workflows. Merge that actually works. >> Faster operations. Version large binaries. Built-in WAN optimization and the >> freedom to use Git, Perforce or both. Make the move to Perforce. >> http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk >> >> >> _______________________________________________ >> Libmesh-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/libmesh-users ------------------------------------------------------------------------------ Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce. With Perforce, you get hassle-free workflows. Merge that actually works. Faster operations. Version large binaries. Built-in WAN optimization and the freedom to use Git, Perforce or both. Make the move to Perforce. http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
