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test_phase_field_deviatoric_split.cc
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Sat, Jul 20, 05:35

test_phase_field_deviatoric_split.cc
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#include "aka_common.hh"
#include "coupler_solid_phasefield.hh"
#include "material.hh"
#include "material_phasefield.hh"
#include "non_linear_solver.hh"
#include "phase_field_model.hh"
#include "solid_mechanics_model.hh"
/* -------------------------------------------------------------------------- */
#include <cmath>
#include <fstream>
#include <iostream>
/* -------------------------------------------------------------------------- */
using namespace akantu;
const UInt spatial_dimension = 2;
/* -------------------------------------------------------------------------- */
void applyDisplacement(SolidMechanicsModel &, Real &);
/* -------------------------------------------------------------------------- */
int main(int argc, char * argv[]) {
std::ofstream os("data.csv");
os << "#strain stress damage analytical_sigma analytical_damage" << std::endl;
initialize("material_hybrid.dat", argc, argv);
Mesh mesh(spatial_dimension);
mesh.read("test_one_element.msh");
CouplerSolidPhaseField coupler(mesh);
auto & model = coupler.getSolidMechanicsModel();
auto & phase = coupler.getPhaseFieldModel();
model.initFull(_analysis_method = _static);
auto & solver = model.getNonLinearSolver("static");
solver.set("max_iterations", 1000);
solver.set("threshold", 1e-6);
solver.set("convergence_type", SolveConvergenceCriteria::_residual);
auto && selector = std::make_shared<MeshDataPhaseFieldSelector<std::string>>(
"physical_names", phase);
phase.setPhaseFieldSelector(selector);
phase.initFull(_analysis_method = _static);
auto & solver_phase = phase.getNonLinearSolver("static");
solver_phase.set("max_iterations", 1000);
solver_phase.set("threshold", 1e-6);
solver_phase.set("convergence_type", SolveConvergenceCriteria::_residual);
model.setBaseName("phase_solid");
model.addDumpField("stress");
model.addDumpField("grad_u");
model.addDumpFieldVector("displacement");
model.addDumpField("damage");
model.dump();
UInt nbSteps = 1500;
Real increment = 1e-4;
auto & stress = model.getMaterial(0).getArray<Real>("stress", _quadrangle_4);
auto & damage = model.getMaterial(0).getArray<Real>("damage", _quadrangle_4);
Real analytical_damage{0.};
Real analytical_sigma{0.};
auto & phasefield = phase.getPhaseField(0);
const Real E = phasefield.getParam("E");
const Real nu = phasefield.getParam("nu");
Real c22 = E * (1 - nu) / ((1 + nu) * (1 - 2 * nu));
const Real lambda = nu * E / ((1. + nu) * (1. - 2. * nu));
const Real mu = E / (2. + 2. * nu);
const Real gc = phasefield.getParam("gc");
const Real l0 = phasefield.getParam("l0");
Real error_stress{0.};
Real error_damage{0.};
Real max_strain_energy{0.};
Real strain_energy_plus{0.};
Real strain_energy_minus{0.};
for (UInt s = 0; s < nbSteps; ++s) {
Real axial_strain{0.};
if (s < 500) {
axial_strain = increment * s;
} else if (s < 1000) {
axial_strain = (1500 - 2 * double(s)) * increment;
} else {
axial_strain = (3 * double(s) - 3500) * increment;
}
applyDisplacement(model, axial_strain);
if (axial_strain > 0) {
strain_energy_plus = axial_strain * axial_strain * (0.5 * lambda + mu);
strain_energy_minus = 0.;
} else {
strain_energy_plus = 0.5 * axial_strain * axial_strain * mu;
strain_energy_minus = axial_strain * axial_strain * 0.5 * (lambda + mu);
}
if (strain_energy_plus > max_strain_energy) {
max_strain_energy = strain_energy_plus;
}
coupler.solve("static", "static");
phase.savePreviousState();
analytical_damage = 2. * (l0 / gc) * max_strain_energy /
(2. * (l0 / gc) * max_strain_energy + 1.);
if (axial_strain < 0.) {
analytical_sigma = (1. - analytical_damage) * (1. - analytical_damage) *
axial_strain * mu +
axial_strain * (lambda + mu);
} else {
analytical_sigma = (lambda + 2. * mu) * axial_strain *
(1. - analytical_damage) * (1. - analytical_damage);
}
error_stress =
std::abs(analytical_sigma - stress(0, 3)) / std::abs(analytical_sigma);
error_damage = std::abs(analytical_damage - damage(0)) / analytical_damage;
os << axial_strain << " " << stress(0, 3) << " " << damage(0) << " "
<< analytical_sigma << " " << analytical_damage << " " << error_stress
<< " " << error_damage << std::endl;
if ((error_damage > 1e-8 or error_stress > 1e-8) and
std::abs(axial_strain) > 1e-13) {
std::cerr << std::left << std::setw(15) << "Step: " << s << std::endl;
std::cerr << std::left << std::setw(15)
<< "Axial strain: " << axial_strain << std::endl;
std::cerr << std::left << std::setw(15)
<< "An. damage: " << analytical_damage << std::endl;
std::cerr << std::left << std::setw(15)
<< "Damage: " << damage(0) << std::endl;
std::cerr << std::left << std::setw(15)
<< "Error damage: " << error_damage << std::endl;
std::cerr << std::left << std::setw(15)
<< "Error stress: " << error_stress << std::endl;
return EXIT_FAILURE;
}
model.dump();
}
os.close();
finalize();
return EXIT_SUCCESS;
}
/* -------------------------------------------------------------------------- */
void applyDisplacement(SolidMechanicsModel & model, Real & increment) {
auto & displacement = model.getDisplacement();
auto & positions = model.getMesh().getNodes();
auto & blocked_dofs = model.getBlockedDOFs();
for (Idx n = 0; n < model.getMesh().getNbNodes(); ++n) {
if (positions(n, 1) == -0.5) {
displacement(n, 0) = 0;
displacement(n, 1) = 0;
blocked_dofs(n, 0) = true;
blocked_dofs(n, 1) = true;
} else {
displacement(n, 0) = 0;
displacement(n, 1) = increment;
blocked_dofs(n, 0) = true;
blocked_dofs(n, 1) = true;
}
}
}
/* -------------------------------------------------------------------------- */

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