Dear Jean-Francois,
Yes, the problem is that integration method in getfem are defined on the element and the boundary of the element not in n-2 dimension structures. If you have a mean to define an integration method on this polyline, then you can assemble your Neumann term. But the only mean, for the moment, to define a 1D integration method on a 3D domain is to define some 1D elements. The problem if you do so is that this integration method will only be defined on the 1D elements, not a the 3D elements on which you want to integrate. So, I think, the only mean which exists right now is to use an interpolation of the 3D fem on the 1D elements and assemble the term. (see interpolation of a fem) It is rather tricky for such a simple operation, but I do not see another "simple" possibility. For Dirichlet condition, you can indeed use add_explicit_matrix to add a constraint on certain nodes or add a constraint brick. For non Lagrange element, you can use the previous strategy to build the constraint matrix, I think. Yves. Jean-Francois Barthelemy <[email protected]> a écrit : > Dear Getfem users, > > Is there any simple way in Getfem to impose lineic boundary conditions on a > 3D problem ? > To be more precise, I have a 3D mesh and I want to impose either Dirichlet > or Neumann boundary conditions on a polyline. The first problem that arises > is that, if I'm not wrong, the mesh_regions in 3D can be either volumes > (convexes) or surfaces (convexe faces) but not 1D elements. However, as I > can gather all the dof corresponding to the polyline, Dirichlet conditions > can rather easily be handled by add_explicit_matrix and add_explicit_rhs > methods. But the case of Neumann conditions may be a bit more difficult. Is > there any straightforward method to do so ? > Thank you very much > > Jean-Francois Barthelemy > _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
