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resolution.cc
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/**
* @file resolution.cc
*
* @author Mohit Pundir <mohit.pundir@epfl.ch>
*
* @date creation: Mon Jan 7 2019
* @date last modification: Mon Jan 7 2019
*
* @brief Implementation of common part of the contact resolution class
*
* @section LICENSE
*
* Copyright (©) 2010-2018 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 "resolution.hh"
#include "contact_mechanics_model.hh"
#include "sparse_matrix.hh"
/* -------------------------------------------------------------------------- */
namespace akantu {
/* -------------------------------------------------------------------------- */
Resolution::Resolution(ContactMechanicsModel & model, const ID & id)
: Memory(id, model.getMemoryID()),
Parsable(ParserType::_contact_resolution, id), fem(model.getFEEngine()),
name(""), model(model),
spatial_dimension(model.getMesh().getSpatialDimension()) {
AKANTU_DEBUG_IN();
this->initialize();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
Resolution::~Resolution() = default;
/* -------------------------------------------------------------------------- */
void Resolution::initialize() {
registerParam("name", name, std::string(), _pat_parsable | _pat_readable);
registerParam("mu", mu, Real(0.), _pat_parsable | _pat_modifiable,
"Friciton Coefficient");
}
/* -------------------------------------------------------------------------- */
void Resolution::printself(std::ostream & stream, int indent) const {
std::string space;
for (Int i = 0; i < indent; i++, space += AKANTU_INDENT)
;
std::string type = getID().substr(getID().find_last_of(':') + 1);
stream << space << "Contact Resolution " << type << " [" << std::endl;
Parsable::printself(stream, indent);
stream << space << "]" << std::endl;
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleInternalForces(GhostType /*ghost_type*/) {
AKANTU_DEBUG_IN();
const auto slave_nodes =
model.getContactDetector().getSurfaceSelector().getSlaveList();
this->assembleInternalForces(slave_nodes);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleInternalForces(const Array<UInt> & slave_nodes) {
AKANTU_DEBUG_IN();
auto & internal_force = const_cast<Array<Real> &>(model.getInternalForce());
auto & nodal_area = const_cast<Array<Real> &>(model.getNodalArea());
auto & contact_map = model.getContactMap();
Array<Real> frequency(internal_force.size(), 1);
for (auto & slave : slave_nodes) {
if (contact_map.find(slave) == contact_map.end())
continue;
auto & element = contact_map[slave];
const auto & conn = element.connectivity;
Vector<Real> contact_force(conn.size() * spatial_dimension);
Vector<Real> n(conn.size() * spatial_dimension);
ResolutionUtils::computeN(n, element);
computeNormalForce(contact_force, n, element);
if (mu != 0) {
Array<Real> t_alpha(conn.size() * spatial_dimension,
spatial_dimension - 1);
Array<Real> n_alpha(conn.size() * spatial_dimension,
spatial_dimension - 1);
Array<Real> d_alpha(conn.size() * spatial_dimension,
spatial_dimension - 1);
ResolutionUtils::computeTalpha(t_alpha, element);
ResolutionUtils::computeNalpha(n_alpha, element);
ResolutionUtils::computeDalpha(d_alpha, n_alpha, t_alpha, element);
computeFrictionalForce(contact_force, d_alpha, element);
}
ResolutionUtils::assembleToInternalForce(contact_force, internal_force,
nodal_area, element, frequency);
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleStiffnessMatrix(GhostType /*ghost_type*/) {
AKANTU_DEBUG_IN();
const auto slave_nodes =
model.getContactDetector().getSurfaceSelector().getSlaveList();
auto & stiffness =
const_cast<SparseMatrix &>(model.getDOFManager().getMatrix("K"));
auto & nodal_area = const_cast<Array<Real> &>(model.getNodalArea());
auto & contact_map = model.getContactMap();
for (auto & slave : slave_nodes) {
if (contact_map.find(slave) == contact_map.end())
continue;
auto & element = contact_map[slave];
const auto & conn = element.connectivity;
Matrix<Real> kc(conn.size() * spatial_dimension,
conn.size() * spatial_dimension);
Matrix<Real> m_alpha_beta(spatial_dimension - 1, spatial_dimension - 1);
ResolutionUtils::computeMetricTensor(m_alpha_beta, element.tangents);
// normal tangent moduli
Vector<Real> n(conn.size() * spatial_dimension);
ResolutionUtils::computeN(n, element);
Array<Real> t_alpha(conn.size() * spatial_dimension, spatial_dimension - 1);
ResolutionUtils::computeTalpha(t_alpha, element);
Array<Real> n_alpha(conn.size() * spatial_dimension, spatial_dimension - 1);
ResolutionUtils::computeNalpha(n_alpha, element);
Array<Real> d_alpha(conn.size() * spatial_dimension, spatial_dimension - 1);
ResolutionUtils::computeDalpha(d_alpha, n_alpha, t_alpha, element);
computeNormalModuli(kc, n_alpha, d_alpha, n, element);
// frictional tangent moduli
if (mu != 0) {
Array<Real> t_alpha_beta(conn.size() * spatial_dimension,
(spatial_dimension - 1) * (spatial_dimension - 1));
ResolutionUtils::computeTalphabeta(t_alpha_beta, element);
Array<Real> p_alpha(conn.size() * spatial_dimension,
spatial_dimension - 1);
Array<Real> n_alpha_beta(conn.size() * spatial_dimension,
(spatial_dimension - 1) * (spatial_dimension - 1));
computeFrictionalTraction(m_alpha_beta, element);
ResolutionUtils::computeNalphabeta(n_alpha_beta, element);
ResolutionUtils::computePalpha(p_alpha, element);
auto phi = computeNablaOfDisplacement(element);
computeFrictionalModuli(kc, t_alpha_beta, n_alpha_beta, n_alpha, d_alpha,
phi, n, element);
}
std::vector<UInt> equations;
UInt nb_degree_of_freedom = model.getSpatialDimension();
std::vector<Real> areas;
for (UInt i : arange(conn.size())) {
UInt n = conn[i];
for (UInt j : arange(nb_degree_of_freedom)) {
equations.push_back(n * nb_degree_of_freedom + j);
areas.push_back(nodal_area[n]);
}
}
for (UInt i : arange(kc.rows())) {
UInt row = equations[i];
for (UInt j : arange(kc.cols())) {
UInt col = equations[j];
kc(i, j) *= areas[i];
stiffness.add(row, col, kc(i, j));
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
Matrix<Real> Resolution::computeNablaOfDisplacement(ContactElement & element) {
const auto & type = element.master.type;
const auto & conn = element.connectivity;
auto surface_dimension = Mesh::getSpatialDimension(type);
auto spatial_dimension = surface_dimension + 1;
auto nb_nodes_per_element = Mesh::getNbNodesPerElement(type);
Matrix<Real> values(spatial_dimension, nb_nodes_per_element);
auto & displacement = model.getDisplacement();
for (UInt n : arange(nb_nodes_per_element)) {
UInt node = conn[n];
for (UInt s : arange(spatial_dimension)) {
values(s, n) = displacement(node, s);
}
}
// Matrix<Real> shape_second_derivatives(surface_dimension *
// surface_dimension, nb_nodes_per_element);
//#define GET_SHAPE_SECOND_DERIVATIVES_NATURAL(type) \
//ElementClass<type>::computeDN2DS2(element.projection, shape_second_derivatives)
// AKANTU_BOOST_ALL_ELEMENT_SWITCH(GET_SHAPE_SECOND_DERIVATIVES_NATURAL);
//#undef GET_SHAPE_SECOND_DERIVATIVES_NATURAL
Matrix<Real> nabla_u(surface_dimension * surface_dimension,
spatial_dimension);
// nabla_u.mul<false, true>(shape_second_derivatives, values);
return nabla_u;
}
} // namespace akantu

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