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rAKA/examples/cohesive_element/cohesive_extrinsic_implicit/cohesive_extrinsic_implicit.cc
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cohesive_extrinsic_implicit.cc
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/**
* @file cohesive_extrinsic_implicit.cc
*
* @author Nicolas Richart <nicolas.richart@epfl.ch>
*
* @date creation: Tue Jan 12 2016
* @date last modification: Mon Jan 18 2016
*
* @brief Example for extrinsic cohesive elements in implicit
*
* @section LICENSE
*
* Copyright (©) 2015 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 "solid_mechanics_model_cohesive.hh"
/* -------------------------------------------------------------------------- */
#include <iostream>
/* -------------------------------------------------------------------------- */
using namespace akantu;
int main(int argc, char * argv[]) {
initialize("material.dat", argc, argv);
debug::setDebugLevel(dblError);
const UInt spatial_dimension = 2;
const UInt max_steps = 20;
const Real final_opening = 1e-4;
Mesh mesh(spatial_dimension);
mesh.read("dcb_2d.msh");
SolidMechanicsModelCohesive model(mesh);
/// model initialization
model.initFull(SolidMechanicsModelCohesiveOptions(_static, true));
// CohesiveElementInserter inserter(mesh);
model.limitInsertion(_y, -0.000001, 0.000001);
model.updateAutomaticInsertion();
Real eps = 1e-11;
Array<bool> & boundary = model.getBlockedDOFs();
Array<Real> & position = mesh.getNodes();
Array<Real> & displacement = model.getDisplacement();
/// boundary conditions
const Vector<Real> & lower = mesh.getLowerBounds();
const Vector<Real> & upper = mesh.getUpperBounds();
const Real left = lower[0];
const Real right = upper[0];
for (UInt n = 0; n < mesh.getNbNodes(); ++n) {
if (std::abs(position(n, 0) - left) < eps) {
boundary(n, 1) = true;
boundary(n, 0) = true;
}
if (std::abs(position(n, 0) - right) < eps && position(n, 1) < 0.0)
boundary(n, 1) = true;
if (std::abs(position(n, 0) - right) < eps && position(n, 1) > 0.0)
boundary(n, 1) = true;
}
model.setBaseName("extr_impl");
model.addDumpFieldVector("displacement");
model.addDumpField("external_force");
model.addDumpField("internal_force");
model.addDumpField("stress");
model.addDumpField("partitions");
model.dump();
// Dumping cohesive elements
model.setBaseNameToDumper("cohesive elements", "cohe_elem_extr_impl");
model.addDumpFieldVectorToDumper("cohesive elements", "displacement");
model.addDumpFieldToDumper("cohesive elements", "damage");
model.dump("cohesive elements");
// model.updateResidual();
Real increment = final_opening / max_steps;
Real tolerance = 1e-13;
Real error;
bool load_reduction = false;
Real tol_increase_factor = 1.0e8;
/// Main loop
for (UInt nstep = 0; nstep < max_steps; ++nstep) {
std::cout << "step no. " << nstep << std::endl;
for (UInt n = 0; n < mesh.getNbNodes(); ++n) {
if (std::abs(position(n, 0) - right) < eps && position(n, 1) > 0.0)
displacement(n, 1) += increment;
if (std::abs(position(n, 0) - right) < eps && position(n, 1) < 0.0)
displacement(n, 1) -= increment;
}
model.solveStepCohesive<_scm_newton_raphson_tangent,
SolveConvergenceCriteria::_increment>(
tolerance, error, 25, load_reduction, tol_increase_factor);
// If convergence has not been reached, the load is reduced and
// the incremental step is solved again.
while (!load_reduction && error > tolerance) {
load_reduction = true;
std::cout << "LOAD STEP REDUCTION" << std::endl;
increment = increment / 2.0;
for (UInt n = 0; n < mesh.getNbNodes(); ++n) {
if (std::abs(position(n, 0) - right) < eps && position(n, 1) > 0.0)
displacement(n, 1) -= increment;
if (std::abs(position(n, 0) - right) < eps && position(n, 1) < 0.0)
displacement(n, 1) += increment;
}
UInt nb_cohesive_elements =
mesh.getNbElement(spatial_dimension, _not_ghost, _ek_cohesive);
model.solveStepCohesive<_scm_newton_raphson_tangent,
SolveConvergenceCriteria::_increment>(
tolerance, error, 25, load_reduction, tol_increase_factor);
UInt new_nb_cohesive_elements =
mesh.getNbElement(spatial_dimension, _not_ghost, _ek_cohesive);
UInt nb_cohe[2];
nb_cohe[0] = nb_cohesive_elements;
nb_cohe[1] = new_nb_cohesive_elements;
// Every time a new cohesive element is introduced, the variable
// load_reduction is set to false, so that it is possible to
// further iterate in the loop of load reduction. If no new
// cohesive elements are introduced, usually there is no gain in
// further reducing the load, even if convergence is not reached
if (nb_cohe[0] == nb_cohe[1])
load_reduction = true;
else
load_reduction = false;
}
model.dump();
model.dump("cohesive elements");
UInt nb_cohe_elems[1];
nb_cohe_elems[0] =
mesh.getNbElement(spatial_dimension, _not_ghost, _ek_cohesive);
std::cout << "No. of cohesive elements: " << nb_cohe_elems[0] << std::endl;
}
finalize();
return EXIT_SUCCESS;
}
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