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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) {
AKANTU_DEBUG_IN();
spatial_dimension = model.getMesh().getSpatialDimension();
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");
registerParam("is_master_deformable", is_master_deformable, bool(false),
_pat_parsable | _pat_readable, "Is master surface deformable");
}
/* -------------------------------------------------------------------------- */
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();
this->assembleInternalForces();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleInternalForces() {
AKANTU_DEBUG_IN();
for (auto & element : model.getContactElements()) {
auto nb_nodes = element.getNbNodes();
Vector<Real> local_fn(nb_nodes * spatial_dimension);
computeNormalForce(element, local_fn);
Vector<Real> local_ft(nb_nodes * spatial_dimension);
computeTangentialForce(element, local_ft);
Vector<Real> local_fc(nb_nodes * spatial_dimension);
local_fc = local_fn + local_ft;
assembleLocalToGlobalArray(element, local_fn, model.getNormalForce());
assembleLocalToGlobalArray(element, local_ft, model.getTangentialForce());
assembleLocalToGlobalArray(element, local_fc, model.getInternalForce());
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleLocalToGlobalArray(const ContactElement & element,
Vector<Real> & local, Array<Real> & global) {
auto get_connectivity = [&](auto & slave, auto & master) {
Vector<UInt> master_conn =
const_cast<const Mesh &>(model.getMesh()).getConnectivity(master);
Vector<UInt> elem_conn(master_conn.size() + 1);
elem_conn[0] = slave;
for (UInt i = 1; i < elem_conn.size(); ++i) {
elem_conn[i] = master_conn[i - 1];
}
return elem_conn;
};
auto connectivity = get_connectivity(element.slave, element.master);
UInt nb_dofs = global.getNbComponent();
UInt nb_nodes = is_master_deformable ? connectivity.size() : 1;
auto & nodal_area = const_cast<Array<Real> &>(model.getNodalArea());
for (UInt i : arange(nb_nodes)) {
UInt n = connectivity[i];
for (UInt j : arange(nb_dofs)) {
UInt offset_node = n * nb_dofs + j;
global[offset_node] += local[i * nb_dofs + j] * nodal_area[element.slave];
}
}
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleStiffnessMatrix(GhostType /*ghost_type*/) {
AKANTU_DEBUG_IN();
auto & global_stiffness =
const_cast<SparseMatrix &>(model.getDOFManager().getMatrix("K"));
auto & gaps = model.getGaps();
auto & projections = model.getProjections();
auto & normals = model.getNormals();
UInt surface_dimension = spatial_dimension - 1;
for (auto & element : model.getContactElements()) {
auto nb_nodes = element.getNbNodes();
Real gap(gaps.begin()[element.slave]);
Vector<Real> normal(normals.begin(spatial_dimension)[element.slave]);
Vector<Real> projection(projections.begin(surface_dimension)[element.slave]);
Matrix<Real> covariant_basis(surface_dimension, spatial_dimension);
GeometryUtils::covariantBasis(model.getMesh(), model.getContactDetector().getPositions(),
element.master, normal, projection, covariant_basis);
Vector<Real> delta_g(nb_nodes * spatial_dimension);
ResolutionUtils::firstVariationNormalGap(element, projection, normal, delta_g);
Matrix<Real> curvature(spatial_dimension,
surface_dimension * surface_dimension);
GeometryUtils::curvature(model.getMesh(), model.getContactDetector().getPositions(),
element.master, projection, curvature);
Matrix<Real> ddelta_g(nb_nodes * spatial_dimension, nb_nodes * spatial_dimension);
ResolutionUtils::secondVariationNormalGap(element, covariant_basis, curvature,
projection, normal, gap, ddelta_g);
Matrix<Real> local_kn(nb_nodes * spatial_dimension, nb_nodes * spatial_dimension);
computeNormalModuli(element, ddelta_g, delta_g, local_kn);
assembleLocalToGlobalMatrix(element, local_kn, global_stiffness);
Matrix<Real> local_kt(nb_nodes * spatial_dimension, nb_nodes * spatial_dimension);
computeTangentialModuli(element, ddelta_g, delta_g, local_kt);
assembleLocalToGlobalMatrix(element, local_kt, global_stiffness);
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void Resolution::assembleLocalToGlobalMatrix(const ContactElement & element,
const Matrix<Real> & local, SparseMatrix & global) {
auto get_connectivity = [&](auto & slave, auto & master) {
Vector<UInt> master_conn =
const_cast<const Mesh &>(model.getMesh()).getConnectivity(master);
Vector<UInt> elem_conn(master_conn.size() + 1);
elem_conn[0] = slave;
for (UInt i = 1; i < elem_conn.size(); ++i) {
elem_conn[i] = master_conn[i - 1];
}
return elem_conn;
};
auto connectivity = get_connectivity(element.slave, element.master);
auto nb_dofs = spatial_dimension;
UInt nb_nodes = is_master_deformable ? connectivity.size() : 1;
UInt total_nb_dofs = nb_dofs * nb_nodes;
std::vector<UInt> equations;
for (UInt i : arange(connectivity.size())) {
UInt conn = connectivity[i];
for (UInt j : arange(nb_dofs)) {
equations.push_back(conn * nb_dofs + j);
}
}
for (UInt i : arange(total_nb_dofs)) {
UInt row = equations[i];
for (UInt j : arange(total_nb_dofs)) {
UInt col = equations[j];
global.add(row, col, local(i, j));
}
}
}
} // namespace akantu

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