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ntrf_friction_mathilde.cc
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ntrf_friction_mathilde.cc
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/**
* @file ntrf_friction_mathilde.cc
* @author David Kammer <david.kammer@epfl.ch>
* @date Thu May 23 16:34:58 2013
*
* @brief implementation of ntrf friction regularized coulomb
*
* @section LICENSE
*
* Copyright (©) 2010-2011 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 "ntrf_friction_mathilde.hh"
__BEGIN_SIMTOOLS__
/* -------------------------------------------------------------------------- */
NTRFFrictionMathilde::NTRFFrictionMathilde(NTRFContact & contact,
const FrictionID & id,
const MemoryID & memory_id) :
NTRFFriction(contact,id,memory_id),
t_star(0,1,0.,id+":t_star",0.,"t_star"),
mu(0,1,0.,id+":mu",0.,"mu"),
frictional_contact_pressure(0,1,0.,id+":frictional_contact_pressure",0.,
"frictional_contact_pressure"),
weakening_length(0,1,0.,id+":weakening_length",0.,"weakening_length"),
mu_s(0,1,0.,id+":mu_s",0.,"mu_s"),
mu_k(0,1,0.,id+":mu_k",0.,"mu_k")
{
AKANTU_DEBUG_IN();
NTRFFriction::registerSynchronizedArray(this->t_star);
NTRFFriction::registerSynchronizedArray(this->weakening_length);
NTRFFriction::registerSynchronizedArray(this->mu_s);
NTRFFriction::registerSynchronizedArray(this->mu_k);
NTRFFriction::registerSynchronizedArray(this->mu);
NTRFFriction::registerSynchronizedArray(this->frictional_contact_pressure);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::computeFrictionalContactPressure() {
AKANTU_DEBUG_IN();
SolidMechanicsModel & model = this->contact->getModel();
UInt dim = model.getSpatialDimension();
UInt nb_contact_nodes = this->contact->getNbContactNodes();
// get contact arrays
const SynchronizedArray<bool> & is_in_contact = this->contact->getIsInContact();
Real * contact_pressure = this->contact->getContactPressure().storage();
for (UInt n=0; n<nb_contact_nodes; ++n) {
// node pair is NOT in contact
if (!is_in_contact(n))
this->frictional_contact_pressure(n) = 0.;
// node pair is in contact
else {
// compute frictional contact pressure
this->frictional_contact_pressure(n) = Math::norm(dim, &(contact_pressure[n*dim]));
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::computeFrictionCoefficient() {
AKANTU_DEBUG_IN();
SolidMechanicsModel & model = this->contact->getModel();
UInt dim = model.getSpatialDimension();
UInt nb_ntn_pairs = this->contact->getNbContactNodes();
for (UInt n=0; n<nb_ntn_pairs; ++n) {
if (this->is_sticking(n)) {
this->mu(n) = this->mu_s(n);
}
else {
if (this->slip(n) >= this->weakening_length(n)) {
this->mu(n) = this->mu_k(n);
}
else {
// mu = mu_k + (1 - slip / Dc) * (mu_s - mu_k)
this->mu(n) = this->mu_k(n)
+ (1 - (this->slip(n) / this->weakening_length(n))) * (this->mu_s(n) - this->mu_k(n));
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::computeFrictionalStrength() {
this->computeFrictionCoefficient();
this->computeFrictionalContactPressure();
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<bool> & is_in_contact = this->contact->getIsInContact();
for (UInt n=0; n<nb_contact_nodes; ++n) {
// node pair is NOT in contact
if (!is_in_contact(n))
this->frictional_strength(n) = 0.;
else {
// compute frictional contact pressure
// backward euler method: first order implicit numerical integration method
// \reg_pres_n+1 = (\reg_pres_n + \delta_t / \t_star * \cur_pres)
// / (1 + \delta_t / \t_star)
Real current_frictional_strength = this->mu(n) * this->frictional_contact_pressure(n);
Real alpha = delta_t / this->t_star(n);
this->frictional_strength(n) += alpha * current_frictional_strength;
this->frictional_strength(n) /= 1 + alpha;
}
}
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::registerSynchronizedArray(SynchronizedArrayBase & array) {
AKANTU_DEBUG_IN();
this->t_star.registerDependingArray(array);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::dumpRestart(const std::string & file_name) const {
AKANTU_DEBUG_IN();
this->t_star.dumpRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::readRestart(const std::string & file_name) {
AKANTU_DEBUG_IN();
this->t_star.readRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setMuS(Real mu) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->mu_s, mu);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setMuS(UInt node, Real mu) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->mu_s, node, mu);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setMuK(Real mu) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->mu_k, mu);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setMuK(UInt node, Real mu) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->mu_k, node, mu);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setWeakeningLength(Real length) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->weakening_length, length);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setWeakeningLength(UInt node, Real length) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->weakening_length, node, length);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setTStar(Real tstar) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->t_star, tstar);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setTStar(UInt node, Real tstar) {
AKANTU_DEBUG_IN();
NTRFFriction::setInternalArray(this->t_star, node, tstar);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::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 << "NTRFFrictionMathilde [" << std::endl;
stream << space << this->t_star << std::endl;
stream << space << "]" << std::endl;
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::setToSteadyState() {
AKANTU_DEBUG_IN();
this->computeFrictionalContactPressure();
this->computeFrictionCoefficient();
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<bool> & is_in_contact = this->contact->getIsInContact();
for (UInt n=0; n<nb_contact_nodes; ++n) {
// node pair is NOT in contact
if (!is_in_contact(n))
this->frictional_strength(n) = 0.;
else {
this->frictional_strength(n) = this->mu(n) * this->frictional_contact_pressure(n);
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTRFFrictionMathilde::addDumpFieldToDumper(const std::string & dumper_name,
const std::string & field_id) {
AKANTU_DEBUG_IN();
#ifdef AKANTU_USE_IOHELPER
// const SynchronizedArray<UInt> * nodal_filter = &(this->contact->getSlaves());
if(field_id == "t_star") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->t_star.getArray()));
}
else if(field_id == "mu") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->mu.getArray()));
}
else if (field_id == "frictional_contact_pressure") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->frictional_contact_pressure.getArray()));
}
else if(field_id == "mu_static") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->mu_s.getArray()));
}
else if(field_id == "mu_kinetic") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->mu_k.getArray()));
}
else if(field_id == "weakening_length") {
this->internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->weakening_length.getArray()));
}
else {
NTRFFriction::addDumpFieldToDumper(dumper_name, field_id);
}
#endif
AKANTU_DEBUG_OUT();
}
__END_SIMTOOLS__

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