Dear Andrew,
This message appear when the level_set function is identically zero on
an element (the level set function have to be "close" to a signed distance).
Are you sure you initialized your level-set function with a correct value ?
Best regards,
Yves.
Le 12/06/2016 23:33, Andrew Roberts a écrit :
> Working to demo 3d XFEM crack propagation of a steel compact specimen
> top-half (gmsh import).
>
> It compiles fine but the executable throws a "level is zero" error
> which I'm uncertain of the source of this error. Code attached below.
>
> /**@file compact.cc
> @brief three-dimensional XFEM crack propagation.
>
> */
>
> #include "getfem/getfem_model_solvers.h"
> #include "getfem/getfem_export.h"
> #include "gmm/gmm.h"
> #include "getfem/getfem_import.h"
> #include "getfem/getfem_assembling.h"
> #include "getfem/getfem_generic_assembly.h"
> #include "getfem/getfem_mesh_im_level_set.h"
> #include "getfem/getfem_mesh_fem_level_set.h"
> #include "getfem/getfem_mesh_fem_product.h"
> #include "getfem/getfem_mesh_fem_global_function.h"
> #include "getfem/getfem_mesh_fem_sum.h"
> #include <string>
> #include <cstring>
> #include <sstream>
> #include <iostream>
>
> using std::endl; using std::cout; using std::cerr;
> using std::ends; using std::cin;
>
> using bgeot::size_type;
> using bgeot::base_node;
> using bgeot::base_small_vector;
> typedef getfem::model_real_plain_vector plain_vector;
>
>
> using bgeot::scalar_type; /* = double */
>
> int main(void) {
>
> double E = 21E6; // Young Modulus (N/cm^2)
> double nu = 0.3; // Poisson ratio
> double clambda = E*nu/((1+nu)*(1-2*nu));
> double cmu = E/(2*(1+nu));
> double clambdastar = 2*clambda*cmu/(clambda+2*cmu);
>
> double residual = 1E-9;
>
> getfem::mesh mesh;
> getfem::import_mesh("gmsh:v4.gmsh.msh",mesh);
>
>
> getfem::mesh_fem mf(mesh, 3);
>
> getfem::mesh_fem mfvm(mesh, 1);
>
> mf.set_finite_element(mesh.convex_index(),
> getfem::fem_descriptor("FEM_PK(3,2)"));
>
> mfvm.set_classical_discontinuous_finite_element(1);
>
> getfem::level_set ls(mesh, 1, true);
> getfem::mesh_level_set mls(mesh);
> mls.add_level_set(ls);
> mls.adapt();
>
> std::vector<getfem::pglobal_function> vfunc(6);
> for (unsigned i = 0; i < vfunc.size(); ++i){
> getfem::abstract_xy_function *s =
> new getfem::crack_singular_xy_function(i);
> getfem::abstract_xy_function *c =
> new getfem::cutoff_xy_function(0, .2,.01,.49);
> s = new getfem::product_of_xy_functions(*s, *c);
> vfunc[i] = getfem::global_function_on_level_set(ls, *s);
> }
>
> getfem::mesh_fem_level_set mfls(mls, mf);
>
> getfem::mesh_fem_global_function mf_sing(mesh,3);
>
> mf_sing.set_functions(vfunc);
>
> getfem::mesh_fem_product mf_asympt(mfls, mf_sing);
>
> getfem::mesh_fem_product mfu(mf_asympt);
>
> getfem::mesh_im_level_set mim(mls,
> getfem::mesh_im_level_set::INTEGRATE_ALL,
> getfem::int_method_descriptor("IM_TETRAHEDRON(6)"),
> getfem::int_method_descriptor("IM_QUASI_POLAR(IM_TETRAHEDRON(8),
> 2)"));
>
>
>
> getfem::model md;
> md.add_fem_variable("u", mfu);
>
>
> md.add_initialized_scalar_data("cmu", cmu);
> md.add_initialized_scalar_data("clambdastar", clambdastar);
>
> getfem::add_isotropic_linearized_elasticity_brick
> (md, mim, "u", "clambdastar", "cmu");
>
>
> getfem::add_normal_Dirichlet_condition_with_multipliers(md,mim,"u", 1,
> 109);
>
> getfem::add_source_term_brick(md,mim,"u","[0,1640,0]", 108);
>
> gmm::iteration iter(residual, 1, 50);
> getfem::standard_solve(md, iter,
> getfem::rselect_linear_solver(md,"superlu"));
>
> getfem::standard_solve(md, iter);
>
> plain_vector U(mfu.nb_dof()); gmm::copy(md.real_variable("u"), U);
> plain_vector VM(mfvm.nb_dof());
> getfem::compute_isotropic_linearized_Von_Mises_or_Tresca
> (md, "u", "clamabdastar", "cmu", mfvm, VM, false);
>
>
> getfem::vtk_export exp2("d_w_vm.vtk", false);
> exp2.exporting(mfu);
> exp2.write_point_data(mfu, U, "displacement");
> exp2.write_point_data(mfvm, VM, "Von Mises stress");
>
>
> }
>
>
> Thank you for any help in advance,
>
> Andy
>
>
> _______________________________________________
> Getfem-users mailing list
> [email protected]
> https://mail.gna.org/listinfo/getfem-users
--
Yves Renard ([email protected]) tel : (33) 04.72.43.87.08
Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29
20, rue Albert Einstein
69621 Villeurbanne Cedex, FRANCE
http://math.univ-lyon1.fr/~renard
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