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test_solid_mechanics_model_dynamics.cc
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test_solid_mechanics_model_dynamics.cc
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/**
* @file test_solid_mechanics_model_dynamics.cc
*
* @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
*
* @date creation: Wed Nov 29 2017
* @date last modification: Wed Feb 21 2018
*
* @brief test of the class SolidMechanicsModel on the 3d cube
*
* @section LICENSE
*
* Copyright (©) 2016-2018 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "boundary_condition_functor.hh"
#include "test_solid_mechanics_model_fixture.hh"
/* -------------------------------------------------------------------------- */
using namespace akantu;
namespace {
const Real A = 1e-1;
const Real E = 1.;
const Real poisson = 3. / 10;
const Real lambda = E * poisson / (1 + poisson) / (1 - 2 * poisson);
const Real mu = E / 2 / (1. + poisson);
const Real rho = 1.;
const Real cp = std::sqrt((lambda + 2 * mu) / rho);
const Real cs = std::sqrt(mu / rho);
const Real c = std::sqrt(E / rho);
const Vector<Real> k = {.5, 0., 0.};
const Vector<Real> psi1 = {0., 0., 1.};
const Vector<Real> psi2 = {0., 1., 0.};
const Real knorm = k.norm();
/* -------------------------------------------------------------------------- */
template <UInt dim> struct Verification {};
/* -------------------------------------------------------------------------- */
template <> struct Verification<1> {
void displacement(Vector<Real> & disp, const Vector<Real> & coord,
Real current_time) {
const auto & x = coord(_x);
const Real omega = c * k[0];
disp(_x) = A * cos(k[0] * x - omega * current_time);
}
void velocity(Vector<Real> & vel, const Vector<Real> & coord,
Real current_time) {
const auto & x = coord(_x);
const Real omega = c * k[0];
vel(_x) = omega * A * sin(k[0] * x - omega * current_time);
}
};
/* -------------------------------------------------------------------------- */
template <> struct Verification<2> {
void displacement(Vector<Real> & disp, const Vector<Real> & X,
Real current_time) {
Vector<Real> kshear = {k[1], k[0]};
Vector<Real> kpush = {k[0], k[1]};
const Real omega_p = knorm * cp;
const Real omega_s = knorm * cs;
Real phase_p = X.dot(kpush) - omega_p * current_time;
Real phase_s = X.dot(kpush) - omega_s * current_time;
disp = A * (kpush * cos(phase_p) + kshear * cos(phase_s));
}
void velocity(Vector<Real> & vel, const Vector<Real> & X, Real current_time) {
Vector<Real> kshear = {k[1], k[0]};
Vector<Real> kpush = {k[0], k[1]};
const Real omega_p = knorm * cp;
const Real omega_s = knorm * cs;
Real phase_p = X.dot(kpush) - omega_p * current_time;
Real phase_s = X.dot(kpush) - omega_s * current_time;
vel =
A * (kpush * omega_p * cos(phase_p) + kshear * omega_s * cos(phase_s));
}
};
/* -------------------------------------------------------------------------- */
template <> struct Verification<3> {
void displacement(Vector<Real> & disp, const Vector<Real> & coord,
Real current_time) {
const auto & X = coord;
Vector<Real> kpush = k;
Vector<Real> kshear1(3);
Vector<Real> kshear2(3);
kshear1.crossProduct(k, psi1);
kshear2.crossProduct(k, psi2);
const Real omega_p = knorm * cp;
const Real omega_s = knorm * cs;
Real phase_p = X.dot(kpush) - omega_p * current_time;
Real phase_s = X.dot(kpush) - omega_s * current_time;
disp = A * (kpush * cos(phase_p) + kshear1 * cos(phase_s) +
kshear2 * cos(phase_s));
}
void velocity(Vector<Real> & vel, const Vector<Real> & coord,
Real current_time) {
const auto & X = coord;
Vector<Real> kpush = k;
Vector<Real> kshear1(3);
Vector<Real> kshear2(3);
kshear1.crossProduct(k, psi1);
kshear2.crossProduct(k, psi2);
const Real omega_p = knorm * cp;
const Real omega_s = knorm * cs;
Real phase_p = X.dot(kpush) - omega_p * current_time;
Real phase_s = X.dot(kpush) - omega_s * current_time;
vel =
A * (kpush * omega_p * cos(phase_p) + kshear1 * omega_s * cos(phase_s) +
kshear2 * omega_s * cos(phase_s));
}
};
/* -------------------------------------------------------------------------- */
template <ElementType _type>
class SolutionFunctor : public BC::Dirichlet::DirichletFunctor {
public:
SolutionFunctor(Real current_time, SolidMechanicsModel & model)
: current_time(current_time), model(model) {}
public:
static constexpr UInt dim = ElementClass<_type>::getSpatialDimension();
inline void operator()(UInt node, Vector<bool> & flags, Vector<Real> & primal,
const Vector<Real> & coord) const {
flags(0) = true;
auto & vel = model.getVelocity();
auto it = vel.begin(model.getSpatialDimension());
Vector<Real> v = it[node];
Verification<dim> verif;
verif.displacement(primal, coord, current_time);
verif.velocity(v, coord, current_time);
}
private:
Real current_time;
SolidMechanicsModel & model;
};
/* -------------------------------------------------------------------------- */
// This fixture uses somewhat finer meshes representing bars.
template <typename type_>
class TestSMMFixtureBar
: public TestSMMFixture<std::tuple_element_t<0, type_>> {
using parent = TestSMMFixture<std::tuple_element_t<0, type_>>;
public:
void SetUp() override {
this->mesh_file =
"../patch_tests/data/bar" + aka::to_string(this->type) + ".msh";
parent::SetUp();
getStaticParser().parse("test_solid_mechanics_model_"
"dynamics_material.dat");
auto analysis_method = std::tuple_element_t<1, type_>::value;
this->model->initFull(_analysis_method = analysis_method);
if (this->dump_paraview) {
std::stringstream base_name;
base_name << "bar" << analysis_method << this->type;
this->model->setBaseName(base_name.str());
this->model->addDumpFieldVector("displacement");
this->model->addDumpField("mass");
this->model->addDumpField("velocity");
this->model->addDumpField("acceleration");
this->model->addDumpFieldVector("external_force");
this->model->addDumpFieldVector("internal_force");
this->model->addDumpField("stress");
this->model->addDumpField("strain");
}
time_step = this->model->getStableTimeStep() / 10.;
this->model->setTimeStep(time_step);
// std::cout << "timestep: " << time_step << std::endl;
const auto & position = this->mesh->getNodes();
auto & displacement = this->model->getDisplacement();
auto & velocity = this->model->getVelocity();
constexpr auto dim = parent::spatial_dimension;
Verification<dim> verif;
for (auto && tuple :
zip(make_view(position, dim), make_view(displacement, dim),
make_view(velocity, dim))) {
verif.displacement(std::get<1>(tuple), std::get<0>(tuple), 0.);
verif.velocity(std::get<2>(tuple), std::get<0>(tuple), 0.);
}
if (dump_paraview)
this->model->dump();
/// boundary conditions
this->model->applyBC(SolutionFunctor<parent::type>(0., *this->model), "BC");
wave_velocity = 1.; // sqrt(E/rho) = sqrt(1/1) = 1
simulation_time = 5 / wave_velocity;
max_steps = simulation_time / time_step; // 100
auto ndump = 50;
dump_freq = max_steps / ndump;
}
protected:
Real time_step;
Real wave_velocity;
Real simulation_time;
UInt max_steps;
UInt dump_freq;
bool dump_paraview{false};
};
template <AnalysisMethod t>
using analysis_method_t = std::integral_constant<AnalysisMethod, t>;
#ifdef AKANTU_IMPLICIT
using TestAnalysisTypes = std::tuple<analysis_method_t<_implicit_dynamic>,
analysis_method_t<_explicit_lumped_mass>>;
#else
using TestAnalysisTypes = std::tuple<analysis_method_t<_explicit_lumped_mass>>;
#endif
using TestTypes =
gtest_list_t<cross_product_t<TestElementTypes, TestAnalysisTypes>>;
TYPED_TEST_CASE(TestSMMFixtureBar, TestTypes);
/* -------------------------------------------------------------------------- */
TYPED_TEST(TestSMMFixtureBar, DynamicsExplicit) {
constexpr auto dim = TestFixture::spatial_dimension;
Real current_time = 0.;
const auto & position = this->mesh->getNodes();
const auto & displacement = this->model->getDisplacement();
UInt nb_nodes = this->mesh->getNbNodes();
UInt nb_global_nodes = this->mesh->getNbGlobalNodes();
Real max_error{0.};
Array<Real> displacement_solution(nb_nodes, dim);
Verification<dim> verif;
for (UInt s = 0; s < this->max_steps; ++s, current_time += this->time_step) {
if (s % this->dump_freq == 0 && this->dump_paraview)
this->model->dump();
/// boundary conditions
this->model->applyBC(
SolutionFunctor<TestFixture::type>(current_time, *this->model), "BC");
// compute the disp solution
for (auto && tuple :
zip(make_view(position, dim), make_view(displacement_solution, dim))) {
verif.displacement(std::get<1>(tuple), std::get<0>(tuple), current_time);
}
// compute the error solution
Real disp_error = 0.;
for (auto && tuple : zip(make_view(displacement, dim),
make_view(displacement_solution, dim))) {
auto diff = std::get<1>(tuple) - std::get<0>(tuple);
disp_error += diff.dot(diff);
}
this->mesh->getCommunicator().allReduce(disp_error,
SynchronizerOperation::_sum);
disp_error = sqrt(disp_error) / nb_global_nodes;
max_error = std::max(disp_error, max_error);
ASSERT_NEAR(disp_error, 0., 2e-3);
this->model->solveStep();
}
// std::cout << "max error: " << max_error << std::endl;
}
}

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