Dear all,
I use getfem to solve a 3D isotropic elastic problem, using a
displacement based FEM
To compute the stress, I have wrote this method:
void getfem_compute_stress(
getfem::model &md,
const std::string &varname,
const std::string &data_lambda,
const std::string &data_mu,
const getfem::mesh_fem &mf_stress,
getfem::model_real_plain_vector &stress )
{
const getfem::mesh_fem *mfu = md.pmesh_fem_of_variable( varname );
GMM_ASSERT1( mfu, "The variable should be a fem variable" );
getfem::size_type N = mfu->linked_mesh().dim();
std::string sigma = data_lambda + "*Div_" + varname +
"*Id(meshdim)+"
+ data_mu + "*(Grad_" + varname + "+Grad_" + varname + "')";
getfem::ga_interpolation_Lagrange_fem( md, sigma, mf_stress,
stress );
}
* md is the model I use to solve the FEM problem
* varname is "u" for the displacement
* data_lambda is "lambda"
* data_mu is "mu"
* mf_stress is a getfem::mesh_fem built with "classical discontinuous
element"
* stress is a vector where the stress will be store
It works like a charm, when I try to visualize the results on paraview,
the stress results are good... but there are continuous !
I am expecting discontinuous result... because I have computed the
displacement field using linear elements, so the stress has to be
constant on each cell.
How can I manage to obtain this kind of result ? I don't want the stress
field to be interpolated ...
Best regards,
Antoine Mazuyer
