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ntn_base_friction.cc
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ntn_base_friction.cc
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/**
* @file ntn_base_friction.cc
*
* @author David Simon Kammer <david.kammer@epfl.ch>
*
* @date creation: Fri Mar 16 2018
* @date last modification: Tue Sep 29 2020
*
* @brief implementation of ntn base friction
*
*
* @section LICENSE
*
* Copyright (©) 2015-2021 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/>.
*
*/
/* -------------------------------------------------------------------------- */
// simtools
#include "ntn_base_friction.hh"
#include "dof_manager_default.hh"
#include "dumper_nodal_field.hh"
#include "dumper_text.hh"
#include "non_linear_solver_lumped.hh"
namespace akantu {
/* -------------------------------------------------------------------------- */
NTNBaseFriction::NTNBaseFriction(NTNBaseContact & contact, const ID & id)
: Parsable(ParserType::_friction, id), contact(contact),
is_sticking(0, 1, true, id + ":is_sticking", true, "is_sticking"),
frictional_strength(0, 1, 0., id + ":frictional_strength", 0.,
"frictional_strength"),
friction_traction(0, contact.getModel().getSpatialDimension(), 0.,
id + ":friction_traction", 0., "friction_traction"),
slip(0, 1, 0., id + ":slip", 0., "slip"),
cumulative_slip(0, 1, 0., id + ":cumulative_slip", 0., "cumulative_slip"),
slip_velocity(0, contact.getModel().getSpatialDimension(), 0.,
id + ":slip_velocity", 0., "slip_velocity") {
AKANTU_DEBUG_IN();
this->contact.registerSynchronizedArray(this->is_sticking);
this->contact.registerSynchronizedArray(this->frictional_strength);
this->contact.registerSynchronizedArray(this->friction_traction);
this->contact.registerSynchronizedArray(this->slip);
this->contact.registerSynchronizedArray(this->cumulative_slip);
this->contact.registerSynchronizedArray(this->slip_velocity);
this->registerExternalDumper(contact.getDumper().shared_from_this(),
contact.getDefaultDumperName(), true);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::updateSlip() {
AKANTU_DEBUG_IN();
SolidMechanicsModel & model = this->contact.getModel();
UInt dim = model.getSpatialDimension();
// synchronize increment
this->contact.getSynchronizerRegistry().synchronize(
SynchronizationTag::_cf_incr);
Array<Real> rel_tan_incr(0, dim);
this->contact.computeRelativeTangentialField(model.getIncrement(),
rel_tan_incr);
Array<Real>::const_iterator<Vector<Real>> it = rel_tan_incr.begin(dim);
UInt nb_nodes = this->contact.getNbContactNodes();
for (UInt n = 0; n < nb_nodes; ++n) {
if (this->is_sticking(n)) {
this->slip(n) = 0.;
} else {
const Vector<Real> & rti = it[n];
this->slip(n) += rti.norm();
this->cumulative_slip(n) += rti.norm();
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::computeFrictionTraction() {
AKANTU_DEBUG_IN();
this->computeStickTraction();
this->computeFrictionalStrength();
SolidMechanicsModel & model = this->contact.getModel();
UInt dim = model.getSpatialDimension();
// get contact arrays
const SynchronizedArray<bool> & is_in_contact =
this->contact.getIsInContact();
auto & traction =
const_cast<Array<Real> &>(this->friction_traction.getArray());
Array<Real>::iterator<Vector<Real>> it_fric_trac = traction.begin(dim);
this->is_sticking.zero(); // set to not sticking
UInt nb_contact_nodes = this->contact.getNbContactNodes();
for (UInt n = 0; n < nb_contact_nodes; ++n) {
// node pair is in contact
if (is_in_contact(n)) {
Vector<Real> fric_trac = it_fric_trac[n];
// check if it is larger than frictional strength
Real abs_fric = fric_trac.norm();
if (abs_fric != 0.) {
Real alpha = this->frictional_strength(n) / abs_fric;
// larger -> sliding
if (alpha < 1.) {
fric_trac *= alpha;
} else {
this->is_sticking(n) = true;
}
} else {
// frictional traction is already zero
this->is_sticking(n) = true;
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::computeStickTraction() {
AKANTU_DEBUG_IN();
SolidMechanicsModel & model = this->contact.getModel();
UInt dim = model.getSpatialDimension();
Real delta_t = model.getTimeStep();
UInt nb_contact_nodes = this->contact.getNbContactNodes();
// get contact arrays
const SynchronizedArray<Real> & impedance = this->contact.getImpedance();
const SynchronizedArray<bool> & is_in_contact =
this->contact.getIsInContact();
Array<Real> acceleration(0, dim);
this->contact.computeAcceleration(acceleration);
// compute relative normal fields of velocity and acceleration
Array<Real> r_velo(0, dim);
Array<Real> r_acce(0, dim);
Array<Real> r_old_acce(0, dim);
this->contact.computeRelativeTangentialField(model.getVelocity(), r_velo);
this->contact.computeRelativeTangentialField(acceleration, r_acce);
this->contact.computeRelativeTangentialField(model.getAcceleration(),
r_old_acce);
AKANTU_DEBUG_ASSERT(r_velo.size() == nb_contact_nodes,
"computeRelativeNormalField does not give back arrays "
<< "size == nb_contact_nodes. nb_contact_nodes = "
<< nb_contact_nodes
<< " | array size = " << r_velo.size());
// compute tangential gap_dot array for all nodes
Array<Real> gap_dot(nb_contact_nodes, dim);
for (auto && data : zip(make_view(gap_dot), make_view(r_velo),
make_view(r_acce), make_view(r_old_acce))) {
auto & gap_dot = std::get<0>(data);
auto & r_velo = std::get<1>(data);
auto & r_acce = std::get<2>(data);
auto & r_old_acce = std::get<3>(data);
gap_dot = r_velo + delta_t * r_acce - 1. / 2. * delta_t * r_old_acce;
}
// compute friction traction to stop sliding
auto & traction =
const_cast<Array<Real> &>(this->friction_traction.getArray());
auto it_fric_trac = traction.begin(dim);
for (UInt n = 0; n < nb_contact_nodes; ++n) {
Vector<Real> fric_trac = it_fric_trac[n];
// node pair is NOT in contact
if (!is_in_contact(n)) {
fric_trac.zero(); // set to zero
}
// node pair is in contact
else {
// compute friction traction
for (UInt d = 0; d < dim; ++d) {
fric_trac(d) = impedance(n) * gap_dot(n, d) / 2.;
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::applyFrictionTraction() {
AKANTU_DEBUG_IN();
SolidMechanicsModel & model = this->contact.getModel();
Array<Real> & residual = model.getInternalForce();
UInt dim = model.getSpatialDimension();
const SynchronizedArray<UInt> & slaves = this->contact.getSlaves();
const SynchronizedArray<Real> & lumped_boundary_slaves =
this->contact.getLumpedBoundarySlaves();
UInt nb_contact_nodes = this->contact.getNbContactNodes();
for (UInt n = 0; n < nb_contact_nodes; ++n) {
UInt slave = slaves(n);
for (UInt d = 0; d < dim; ++d) {
residual(slave, d) -=
lumped_boundary_slaves(n) * this->friction_traction(n, d);
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::registerSynchronizedArray(SynchronizedArrayBase & array) {
AKANTU_DEBUG_IN();
this->frictional_strength.registerDependingArray(array);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::dumpRestart(const std::string & file_name) const {
AKANTU_DEBUG_IN();
this->is_sticking.dumpRestartFile(file_name);
this->frictional_strength.dumpRestartFile(file_name);
this->friction_traction.dumpRestartFile(file_name);
this->slip.dumpRestartFile(file_name);
this->cumulative_slip.dumpRestartFile(file_name);
this->slip_velocity.dumpRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::readRestart(const std::string & file_name) {
AKANTU_DEBUG_IN();
this->is_sticking.readRestartFile(file_name);
this->frictional_strength.readRestartFile(file_name);
this->friction_traction.readRestartFile(file_name);
this->cumulative_slip.readRestartFile(file_name);
this->slip_velocity.readRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::setParam(const std::string & name, UInt node,
Real value) {
AKANTU_DEBUG_IN();
auto & array = this->get(name).get<SynchronizedArray<Real>>();
Int index = this->contact.getNodeIndex(node);
if (index < 0) {
AKANTU_DEBUG_WARNING("Node "
<< node << " is not a contact node. "
<< "Therefore, cannot set interface parameter!!");
} else {
array(index) = value; // put value
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
UInt NTNBaseFriction::getNbStickingNodes() const {
AKANTU_DEBUG_IN();
UInt nb_stick = 0;
UInt nb_nodes = this->contact.getNbContactNodes();
const SynchronizedArray<UInt> & nodes = this->contact.getSlaves();
const SynchronizedArray<bool> & is_in_contact =
this->contact.getIsInContact();
const Mesh & mesh = this->contact.getModel().getMesh();
for (UInt n = 0; n < nb_nodes; ++n) {
bool is_local_node = mesh.isLocalOrMasterNode(nodes(n));
bool is_pbc_slave_node = mesh.isPeriodicSlave(nodes(n));
if (is_local_node && !is_pbc_slave_node && is_in_contact(n) &&
this->is_sticking(n)) {
nb_stick++;
}
}
mesh.getCommunicator().allReduce(nb_stick, SynchronizerOperation::_sum);
AKANTU_DEBUG_OUT();
return nb_stick;
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::printself(std::ostream & stream, int indent) const {
AKANTU_DEBUG_IN();
std::string space;
for (Int i = 0; i < indent; i++, space += AKANTU_INDENT) {
;
}
stream << space << "NTNBaseFriction [" << std::endl;
Parsable::printself(stream, indent);
stream << space << "]" << std::endl;
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNBaseFriction::addDumpFieldToDumper(const std::string & dumper_name,
const std::string & field_id) {
AKANTU_DEBUG_IN();
if (field_id == "is_sticking") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<bool>>(
this->is_sticking.getArray()));
} else if (field_id == "frictional_strength") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<Real>>(
this->frictional_strength.getArray()));
} else if (field_id == "friction_traction") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<Real>>(
this->friction_traction.getArray()));
} else if (field_id == "slip") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<Real>>(this->slip.getArray()));
} else if (field_id == "cumulative_slip") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<Real>>(
this->cumulative_slip.getArray()));
} else if (field_id == "slip_velocity") {
this->internalAddDumpFieldToDumper(
dumper_name, field_id,
std::make_unique<dumpers::NodalField<Real>>(
this->slip_velocity.getArray()));
} else {
this->contact.addDumpFieldToDumper(dumper_name, field_id);
}
AKANTU_DEBUG_OUT();
}
} // namespace akantu

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