Thank you so much. I will have a look! On Wednesday, August 1, 2018 at 1:58:27 PM UTC+1, Jean-Paul Pelteret wrote: > > Dear Jane, > > The method described by Claire is exactly the approach used by my > colleagues to model additive manufacturing processes. See, for example, > this paper > 10.1007/s00170-016-8819-6 <https://dx.doi.org/10.1007/s00170-016-8819-6> and > maybe others by D. Riedlbauer > <https://www.ltm.tf.fau.eu/chair-of-applied-mechanics/publications/> that > perhaps explain the approach in more detail. > > Best, > Jean-Paul > > On 01 Aug 2018, at 14:20, Claire <claire....@gmail.com <javascript:>> > wrote: > > Dear Jane, > > If I got well what you want to do I would suggest I a different approach, > namely an "element birth" technique. > It can be implemented in deal.ii using FE_Nothing elements and the hp:: > namespace > > https://dealii.org/9.0.0/doxygen/deal.II/classFE__Nothing.html > https://dealii.org/9.0.0/doxygen/deal.II/namespacehp.html > > More practically, instead of adding cells to your triangulation, create > from the beginning the final domain you want to simulate. > Then you set the fe_index of the cells that belong to the domain you don't > want to solve yet the one of FE_Nothing in your FECollection. > This finite element has no degree of freedom, so nothing will happen there. > > When you want to activate one cell, just turn its fe_index to the one > corresponding to "FE_Something" in your FECollection. > > I hope my brief explanation was clear enough, and that this suggestion is > relevant for your problem. > If you ever need further information, don't hesitate to ask. > > Best, > > Claire > > Le lundi 30 juillet 2018 12:39:34 UTC+2, Jane Lee a écrit : >> >> >> Hi all, >> >> I'm a little stuck on a problem and hope that someone can suggest >> something. >> >> I am solving a problem where I need to add a thin layer onto a domain >> which I move after solving each solution; >> 1. I solve for the velocity >> 2. I then move the mesh by using a vertex displacement method like in >> step-18 (it works fine til up here) >> 3. I create a domain using the top boundary vertices of the resulting >> mesh in 2. and I want to add it to the same mesh and solve again. >> (The background is that I want to deposit a layer of material on top of >> the existing one to represent sedimentation). >> >> I have tried using both create_union_triangulation and >> merge_triangulations and problem is as follows: >> I am using a subdivided hyper rectangle as the original mesh then >> refining before I do 1. of above. This means that when i create the domain >> in 3. with the vertex points of the top boundary, the created mesh has a >> different coarse grid than the first, so I am getting the error that they >> are not derived from the coarse mesh. >> >> Can anyone suggest a way to coarsen both meshes so that the merging >> works? I also seem to have the problem that my original grid doesn't >> coarsen all the way back to the initial subdivided rectangle and not sure >> why..... >> >> And after that, would i have to interpolate the solution on the old mesh >> back first then some other solution on the created mesh (which I know) >> BEFORE i merge? >> >> Many thanks >> >> Sample codes at each step: >> >> 2. move mesh >> >> for (typename DoFHandler<dim>::active_cell_iterator >> >> cell = dof_handler.begin_active (); >> >> cell != dof_handler.end(); ++cell) >> >> for (unsigned int v=0; >> v<GeometryInfo<dim>::vertices_per_cell; ++v) >> >> if (vertex_touched[cell->vertex_index(v)] == false) >> >> { >> >> vertex_touched[cell->vertex_index(v)] = true; >> >> Point<dim> vertex_displacement; >> >> for (unsigned int d=0; d<dim; ++d) >> >> {vertex_displacement[d] >> >> = solution.block(0)(cell->vertex_dof_index(v,d)); >> >> } >> >> cell->vertex(v) += vertex_displacement*timestep_size; >> >> // std::cout << cell->diameter() >> << std::endl; >> >> } >> >> >> 3. creating top domain (then the last bit doesn't work) >> >> print_mesh_info(triangulation, "after_solving_grid.eps"); >> >> >> std::vector<Point<2>> vertex_points; >> >> vertex_points.push_back (Point<dim> (0,1.)); >> >> unsigned int p = 0; >> >> >> for (typename Triangulation<dim>::active_cell_iterator >> >> cell = triangulation.begin_active(); >> >> cell != triangulation.end(); ++cell) >> >> { >> >> for (unsigned int f=0; f<GeometryInfo<dim>::faces_per_cell; >> ++f) >> >> { >> >> if (cell->face(f)->boundary_id() == 1) >> >> { >> >> Point<2> points = cell->face(f)->vertex(1); >> >> // std::cout << points << std::endl; >> >> vertex_points.push_back (points); >> >> ++p; >> >> } >> >> } >> >> } >> >> >> const double end_z_point = vertex_points[vertex_points.size()-1][ >> 1]; >> >> >> // Output vertices of top of old domain. >> >> for (unsigned int i=0; i<=vertex_points.size()-1; ++i) >> >> std::cout << vertex_points[i] << std::endl; >> >> >> // Number of vertices along boundary >> >> const int no_vertex_bdry = vertex_points.size(); >> >> std::cout << "Number of vertex points: " << no_vertex_bdry >> <<std::endl; >> >> >> for (unsigned int i=0; i<no_vertex_bdry; ++i) >> >> { >> >> vertex_points.push_back (Point<dim> (vertex_points[i][0], >> vertex_points[i][1]+sed_height)); >> >> } >> >> >> // output vertex points of new deposited layer >> >> const int no_vertex_total = no_vertex_bdry*2; >> >> for (unsigned int i=0; i<no_vertex_total; ++i) >> >> std::cout << vertex_points[i] << std::endl; >> >> >> // >> >> // // numbering will go from 0 to vertex_length-1 >> >> >> const int n = no_vertex_bdry-1; >> >> const int m = GeometryInfo<dim>::vertices_per_cell; >> >> unsigned int cell_vertices[n][m];// = {0}; >> >> >> for (unsigned int i=0; i<n; ++i) >> >> { >> >> cell_vertices[i][0] = i; >> >> cell_vertices[i][1] = i+1; >> >> cell_vertices[i][2] = no_vertex_bdry + i; >> >> cell_vertices[i][3] = no_vertex_bdry + i+1; >> >> std::cout << cell_vertices[i][3] << std::endl; >> >> } >> >> >> const unsigned int >> >> n_cells = sizeof(cell_vertices) / sizeof(cell_vertices[0]); >> >> std::vector<CellData<dim> > cells (n_cells, CellData<dim>()); >> >> for (unsigned int i=0; i<n_cells; ++i) >> >> { >> >> for (unsigned int j=0; >> >> j<GeometryInfo<dim>::vertices_per_cell; >> >> ++j) >> >> cells[i].vertices[j] = cell_vertices[i][j]; >> >> cells[i].material_id = 0; >> >> } >> >> >> sediment_tria.create_triangulation (vertex_points, cells, >> SubCellData()); >> >> >> print_mesh_info(sediment_tria, "sediment_grid_refined.eps"); >> >> >> for (typename Triangulation<dim>::active_cell_iterator >> >> cell = sediment_tria.begin_active(); >> >> cell != sediment_tria.end(); ++cell) >> >> { >> >> cell->set_coarsen_flag(); >> >> } >> >> >> sediment_tria.execute_coarsening_and_refinement (); >> >> >> print_mesh_info(sediment_tria, "sediment_grid_coarse.eps"); >> >> // >> >> // for (typename Triangulation<dim>::active_cell_iterator >> >> // cell = triangulation.begin_active(); >> >> // cell != triangulation.end(); ++cell) >> >> // { >> >> // cell->set_coarsen_flag(); >> >> // } >> >> // >> >> // triangulation.execute_coarsening_and_refinement (); >> >> // print_mesh_info(triangulation, "initial_grid.eps"); >> >> // >> >> // GridGenerator::create_union_triangulation (sediment_tria, >> triangulation, final_tria); >> >> // print_mesh_info(final_tria, >> "final_grid.eps"); >> >> > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to dealii+un...@googlegroups.com <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > >
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