Hello Mr.Bangerth. Thank you very much for your input and your help. I did
implement the same loop actually in my code but i am getting a segmentation
fault but i guess this is a minor issue that i cannot find. Maybe because
it is my first code in c++ and using deal ii.
My debugger seems to not work properly. Maybe you can find the issue if i
post some of the code:
This is my PointHistory class with old_stress included:
* template <int dim,typename NumberType>*
* class PointHistory*
* {*
* public:*
* PointHistory()*
* : old_stress(SymmetricTensor<2, dim,NumberType>())*
* {}*
* virtual ~PointHistory()*
* {}*
* // The first function is used to create a material object and to*
* // initialize all tensors correctly: The second one updates the stored*
* // values and stresses based on the current deformation measure*
* // $\textrm{Grad}\mathbf{u}_{\textrm{n}}$.*
* void setup_lqp (const Parameters::AllParameters ¶meters)*
* {*
* material =*
*
std::make_shared<Material_Compressible_Neo_Hook_One_Field_Pert<dim,NumberType>>(*
* parameters.mu, parameters.nu);*
* update_values(Tensor<2, dim,NumberType>());*
* }*
* void update_values(const Tensor<2, dim,NumberType> &Grad_u_n)*
* {*
* const Tensor<2, dim> F =
Physics::Elasticity::Kinematics::F(Grad_u_n);*
* const NumberType det_F = determinant(F);*
* const SymmetricTensor<2,dim,NumberType> C =
Physics::Elasticity::Kinematics::C(F);*
* old_stress = material->get_s_piola(det_F,C);*
* }*
* NumberType get_det_F() const*
* {*
* return material->get_det_F();*
* }*
* const SymmetricTensor<2, dim,NumberType> get_C() const*
* {*
* return material->get_C;*
* } *
* // We offer an interface to retrieve certain data.*
* // This is the strain energy:*
*/* NumberType*
* get_Psi(const NumberType &det_F,*
* const SymmetricTensor<2,dim,NumberType> &b_bar) const*
* {*
* return material->get_Psi(det_F,b_bar);*
* } */*
* // Here are the kinetic variables. These are used in the material and*
* // global tangent matrix and residual assembly operations:*
* // First is the Kirchhoff stress:*
* SymmetricTensor<2,dim,NumberType>*
* get_s_piola(const NumberType &det_F,*
* const SymmetricTensor<2,dim,NumberType> &C) const*
* {*
* return material->get_s_piola(det_F,C);*
* }*
* // And the tangent:*
* SymmetricTensor<4,dim,NumberType>*
* get_Jc(const Tensor<2, dim, NumberType> &F,*
* const SymmetricTensor<2,dim,NumberType> &S,*
* const Tensor<2, dim, NumberType> &F_inv,*
* const NumberType &det_F,*
* const SymmetricTensor<2,dim,NumberType> &C) const*
* {*
* return material->get_Jc(F,S,F_inv,det_F,C);*
* }*
* SymmetricTensor<2,dim,NumberType> old_stress;*
* // In terms of member functions, this class stores for the quadrature*
* // point it represents a copy of a material type in case different*
* // materials are used in different regions of the domain, as well as
the*
* // inverse of the deformation gradient...*
* private:*
* std::shared_ptr<
Material_Compressible_Neo_Hook_One_Field_Pert<dim,NumberType> > material;*
* };*
I update my old_stress by using the update_values void like in step 44.
And here is my output_results void:
* template <int dim,typename NumberType>*
* void Solid<dim,NumberType>::output_results() const*
* {*
* DataOut<dim> data_out;*
* std::vector<DataComponentInterpretation::DataComponentInterpretation>*
* data_component_interpretation(dim,*
*
DataComponentInterpretation::component_is_part_of_vector);*
* std::vector<std::string> solution_name(dim, "displacement");*
* data_out.attach_dof_handler(dof_handler_ref);*
* data_out.add_data_vector(solution_n,*
* solution_name,*
* DataOut<dim>::type_dof_data,*
* data_component_interpretation);*
* Postprocessor<dim> postprocessor;*
* data_out.add_data_vector(solution_n, postprocessor);*
* Vector<double> norm_of_stress(triangulation.n_active_cells());*
* for (auto &cell : triangulation.active_cell_iterators()){*
* if (cell->is_locally_owned())*
* {*
* SymmetricTensor<2, dim> accumulated_stress;*
* printf("\n cell owned\n");*
* for (unsigned int q = 0; q < qf_cell.size(); ++q){*
* std::cout<<q<<" ";*
* accumulated_stress +=*
* reinterpret_cast<PointHistory<dim,NumberType>
*>(cell->user_pointer())[q].old_stress;*
* }*
* }*
* } *
* Vector<double> soln(solution_n.size());*
* for (unsigned int i = 0; i < soln.size(); ++i)*
* soln(i) = solution_n(i);*
* MappingQEulerian<dim> q_mapping(degree, dof_handler_ref, soln);*
* data_out.build_patches(q_mapping, degree);*
* std::ostringstream filename;*
* filename << "solution-" << time.get_timestep() << ".vtk";*
* std::ofstream output(filename.str().c_str());*
* data_out.write_vtk(output);*
* }*
*}*
Wolfgang Bangerth schrieb am Freitag, 20. Mai 2022 um 02:02:33 UTC+2:
> On 5/19/22 00:47, BBah wrote:
> >
> > i am just trying to put out the norm of the stresses like in step 18. Is
> there
> > a way to save my stress tensor for each cell and put it out ? In step 18
> there
> > is a loop through each cell and the locally owned are used to put out
> the
> > stresses. Is there a way to do the same with the workstream object ?
> Been
> > searching for a while for a solution but could not find one. Putting out
> the
> > strains is easy since the gradient of the displacements are saved but
> how to
> > do the same with the stresses ?
>
> BBah: What have you tried already? When you loop over all cells with
> WorkStream, the WorkStream::run() function calls your 'worker' function
> for
> every cell. This is the place where you would create output.
>
> Alternatively, if all you want is to generate some output, just do it with
> the
> same loop as done in step-18. WorkStream is meant for cases where
> something is
> expensive and you want to do it in parallel, but outputting a couple of
> numbers for each cell is not expensive.
>
> Best
> WB
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: bang...@colostate.edu
> www: http://www.math.colostate.edu/~bangerth/
>
>
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