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ntn_contact.cc
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/**
* @file ntn_contact.cc
* @author David Kammer <david.kammer@epfl.ch>
* @date Thu Mar 14 11:52:00 2013
*
* @brief implementation of ntn_contact
*
* @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 "ntn_contact.hh"
#include "dumper_text.hh"
__BEGIN_SIMTOOLS__
/* -------------------------------------------------------------------------- */
NTNContact::NTNContact(SolidMechanicsModel & model,
const ContactID & id,
const MemoryID & memory_id) :
NTNBaseContact(model,id,memory_id),
masters(0,1,0,id+":masters",std::numeric_limits<UInt>::quiet_NaN(),"masters"),
lumped_boundary_masters(0,1,0,id+":lumped_boundary_masters",
std::numeric_limits<Real>::quiet_NaN(),"lumped_boundary_masters"),
master_elements("master_elements", id, memory_id)
{
AKANTU_DEBUG_IN();
const Mesh & mesh = this->model.getMesh();
UInt spatial_dimension = this->model.getSpatialDimension();
mesh.initElementTypeMapArray(this->master_elements,
1,
spatial_dimension - 1);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::pairInterfaceNodes(const ElementGroup & slave_boundary,
const ElementGroup & master_boundary,
UInt surface_normal_dir,
const Mesh & mesh,
Array<UInt> & pairs) {
AKANTU_DEBUG_IN();
pairs.resize(0);
AKANTU_DEBUG_ASSERT(pairs.getNbComponent() == 2,
"Array of node pairs should have nb_component = 2," <<
" but has nb_component = " << pairs.getNbComponent());
UInt dim = mesh.getSpatialDimension();
AKANTU_DEBUG_ASSERT(surface_normal_dir < dim, "Mesh is of " << dim << " dimensions"
<< " and cannot have direction " << surface_normal_dir
<< " for surface normal");
// offset for projection computation
UInt offset[dim-1];
for (UInt i=0, j=0; i<dim; ++i) {
if (surface_normal_dir != i) {
offset[j] = i;
++j;
}
}
// find projected node coordinates
const Array<Real> & coordinates = mesh.getNodes();
// find slave nodes
Array<Real> proj_slave_coord(slave_boundary.getNbNodes(),dim-1,0.);
Array<UInt> slave_nodes(slave_boundary.getNbNodes());
UInt n(0);
for(ElementGroup::const_node_iterator nodes_it(slave_boundary.node_begin()); nodes_it!= slave_boundary.node_end(); ++nodes_it) {
for (UInt d=0; d<dim-1; ++d) {
proj_slave_coord(n,d) = coordinates(*nodes_it,offset[d]);
slave_nodes(n)=*nodes_it;
}
++n;
}
// find master nodes
Array<Real> proj_master_coord(master_boundary.getNbNodes(),dim-1,0.);
Array<UInt> master_nodes(master_boundary.getNbNodes());
n=0;
for(ElementGroup::const_node_iterator nodes_it(master_boundary.node_begin()); nodes_it!= master_boundary.node_end(); ++nodes_it) {
for (UInt d=0; d<dim-1; ++d) {
proj_master_coord(n,d) = coordinates(*nodes_it,offset[d]);
master_nodes(n)=*nodes_it;
}
++n;
}
// find minimum distance between slave nodes to define tolerance
Real min_dist = std::numeric_limits<Real>::max();
for (UInt i=0; i<proj_slave_coord.getSize(); ++i) {
for (UInt j=i+1; j<proj_slave_coord.getSize(); ++j) {
Real dist = 0.;
for (UInt d=0; d<dim-1; ++d) {
dist += (proj_slave_coord(i,d) - proj_slave_coord(j,d))
* (proj_slave_coord(i,d) - proj_slave_coord(j,d));
}
if (dist < min_dist) {
min_dist = dist;
}
}
}
min_dist = std::sqrt(min_dist);
Real local_tol = 0.1*min_dist;
// find master slave node pairs
for (UInt i=0; i<proj_slave_coord.getSize(); ++i) {
for (UInt j=0; j<proj_master_coord.getSize(); ++j) {
Real dist = 0.;
for (UInt d=0; d<dim-1; ++d) {
dist += (proj_slave_coord(i,d) - proj_master_coord(j,d))
* (proj_slave_coord(i,d) - proj_master_coord(j,d));
}
dist = std::sqrt(dist);
if (dist < local_tol) { // it is a pair
UInt pair[2];
pair[0] = slave_nodes(i);
pair[1] = master_nodes(j);
pairs.push_back(pair);
continue; // found master do not need to search further for this slave
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::addSurfacePair(const Surface & slave,
const Surface & master,
UInt surface_normal_dir) {
AKANTU_DEBUG_IN();
const Mesh & mesh = this->model.getMesh();
const ElementGroup & slave_boundary = mesh.getElementGroup(slave);
const ElementGroup & master_boundary = mesh.getElementGroup(master);
this->contact_surfaces.insert(&slave_boundary);
this->contact_surfaces.insert(&master_boundary);
Array<UInt> pairs(0,2);
NTNContact::pairInterfaceNodes(slave_boundary,
master_boundary,
surface_normal_dir,
this->model.getMesh(),
pairs);
// eliminate pairs which contain a pbc slave node
Array<UInt> pairs_no_PBC_slaves(0,2);
Array<UInt>::const_vector_iterator it = pairs.begin(2);
Array<UInt>::const_vector_iterator end = pairs.end(2);
for (; it!=end; ++it) {
const Vector<UInt> & pair = *it;
if (!this->model.isPBCSlaveNode(pair(0)) && !this->model.isPBCSlaveNode(pair(1))) {
pairs_no_PBC_slaves.push_back(pair);
}
}
this->addNodePairs(pairs_no_PBC_slaves);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::addNodePairs(const Array<UInt> & pairs) {
AKANTU_DEBUG_IN();
AKANTU_DEBUG_ASSERT(pairs.getNbComponent() == 2,
"Array of node pairs should have nb_component = 2," <<
" but has nb_component = " << pairs.getNbComponent());
UInt nb_pairs = pairs.getSize();
for (UInt n=0; n<nb_pairs; ++n) {
this->addSplitNode(pairs(n,0), pairs(n,1));
}
// synchronize with depending nodes
findBoundaryElements(this->slaves.getArray(), this->slave_elements);
findBoundaryElements(this->masters.getArray(), this->master_elements);
updateInternalData();
syncArrays(_added);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::getNodePairs(Array<UInt> & pairs) const {
AKANTU_DEBUG_IN();
pairs.resize(0);
AKANTU_DEBUG_ASSERT(pairs.getNbComponent() == 2,
"Array of node pairs should have nb_component = 2," <<
" but has nb_component = " << pairs.getNbComponent());
UInt nb_pairs = this->getNbContactNodes();
for (UInt n=0; n<nb_pairs; ++n) {
UInt pair[2];
pair[0] = this->slaves(n);
pair[1] = this->masters(n);
pairs.push_back(pair);
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::addSplitNode(UInt slave, UInt master) {
AKANTU_DEBUG_IN();
NTNBaseContact::addSplitNode(slave);
this->masters.push_back(master);
this->lumped_boundary_masters.push_back(std::numeric_limits<Real>::quiet_NaN());
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
/*
This function only works for surface elements with one quad point. For
surface elements with more quad points, it computes still, but the result
might not be what you are looking for.
*/
void NTNContact::updateNormals() {
AKANTU_DEBUG_IN();
// set normals to zero
this->normals.clear();
// contact information
UInt dim = this->model.getSpatialDimension();
UInt nb_contact_nodes = this->getNbContactNodes();
this->synch_registry->synchronize(_gst_cf_nodal); // synchronize current pos
const Array<Real> & cur_pos = this->model.getCurrentPosition();
FEEngine & boundary_fem = this->model.getFEEngineBoundary();
const Mesh & mesh = this->model.getMesh();
for (ghost_type_t::iterator gt = ghost_type_t::begin();
gt != ghost_type_t::end();
++gt) {
Mesh::type_iterator it = mesh.firstType(dim-1, *gt);
Mesh::type_iterator last = mesh.lastType(dim-1, *gt);
for (; it != last; ++it) {
// get elements connected to each node
CSR<UInt> node_to_element;
MeshUtils::buildNode2ElementsElementTypeMap(mesh, node_to_element, *it, *gt);
// compute the normals
Array<Real> quad_normals(0,dim);
boundary_fem.computeNormalsOnControlPoints(cur_pos, quad_normals, *it, *gt);
UInt nb_quad_points = boundary_fem.getNbQuadraturePoints(*it, *gt);
// add up normals to all master nodes
for (UInt n=0; n<nb_contact_nodes; ++n) {
UInt master = this->masters(n);
CSR<UInt>::iterator elem = node_to_element.begin(master);
// loop over all elements connected to this master node
for (; elem != node_to_element.end(master); ++elem) {
UInt e = *elem;
// loop over all quad points of this element
for (UInt q=0; q<nb_quad_points; ++q) {
// add quad normal to master normal
for (UInt d=0; d<dim; ++d) {
this->normals(n,d) += quad_normals(e*nb_quad_points + q, d);
}
}
}
}
}
}
Real * master_normals = this->normals.storage();
for (UInt n=0; n<nb_contact_nodes; ++n) {
if (dim==2)
Math::normalize2(&(master_normals[n*dim]));
else if (dim==3)
Math::normalize3(&(master_normals[n*dim]));
}
// // normalize normals
// Array<Real>::iterator<Real> nit = this->normals.begin();
// Array<Real>::iterator<Real> nend = this->normals.end();
// for (; nit != nend; ++nit) {
// nit->normalize();
// }
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::dumpRestart(const std::string & file_name) const {
AKANTU_DEBUG_IN();
NTNBaseContact::dumpRestart(file_name);
this->masters.dumpRestartFile(file_name);
this->lumped_boundary_masters.dumpRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::readRestart(const std::string & file_name) {
AKANTU_DEBUG_IN();
NTNBaseContact::readRestart(file_name);
this->masters.readRestartFile(file_name);
this->lumped_boundary_masters.readRestartFile(file_name);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::updateImpedance() {
AKANTU_DEBUG_IN();
UInt nb_contact_nodes = getNbContactNodes();
Real delta_t = this->model.getTimeStep();
AKANTU_DEBUG_ASSERT(delta_t != NAN, "Time step is NAN. Have you set it already?");
const Array<Real> & mass = this->model.getMass();
for (UInt n=0; n<nb_contact_nodes; ++n) {
UInt master = this->masters(n);
UInt slave = this->slaves(n);
Real imp = (this->lumped_boundary_masters(n) / mass(master))
+ (this->lumped_boundary_slaves(n) / mass(slave));
imp = 2 / delta_t / imp;
this->impedance(n) = imp;
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::updateLumpedBoundary() {
AKANTU_DEBUG_IN();
internalUpdateLumpedBoundary(this->slaves.getArray(),
this->slave_elements,
this->lumped_boundary_slaves);
internalUpdateLumpedBoundary(this->masters.getArray(),
this->master_elements,
this->lumped_boundary_masters);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::applyContactPressure() {
AKANTU_DEBUG_IN();
UInt nb_ntn_pairs = getNbContactNodes();
UInt dim = this->model.getSpatialDimension();
Array<Real> & residual = this->model.getResidual();
for (UInt n=0; n<nb_ntn_pairs; ++n) {
UInt master = this->masters(n);
UInt slave = this->slaves(n);
for (UInt d=0; d<dim; ++d) {
residual(master,d) += this->lumped_boundary_masters(n) * this->contact_pressure(n,d);
residual(slave, d) -= this->lumped_boundary_slaves(n) * this->contact_pressure(n,d);
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::computeRelativeTangentialField(const Array<Real> & field,
Array<Real> & rel_tang_field) const {
AKANTU_DEBUG_IN();
// resize arrays to zero
rel_tang_field.resize(0);
UInt dim = this->model.getSpatialDimension();
Array<Real>::const_vector_iterator it_field = field.begin(dim);
Array<Real>::const_vector_iterator it_normal = this->normals.getArray().begin(dim);
Vector<Real> rfv(dim);
Vector<Real> np_rfv(dim);
UInt nb_contact_nodes = this->slaves.getSize();
for (UInt n=0; n<nb_contact_nodes; ++n) {
// nodes
UInt slave = this->slaves(n);
UInt master = this->masters(n);
// relative field vector (slave - master)
rfv = it_field[slave];
rfv -= it_field[master];
// normal projection of relative field
const Vector<Real> & normal_v = it_normal[n];
np_rfv = normal_v;
np_rfv *= rfv.dot(normal_v);
// subract normal projection from relative field to get the tangential projection
rfv -= np_rfv;
rel_tang_field.push_back(rfv);
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::computeRelativeNormalField(const Array<Real> & field,
Array<Real> & rel_normal_field) const {
AKANTU_DEBUG_IN();
// resize arrays to zero
rel_normal_field.resize(0);
UInt dim = this->model.getSpatialDimension();
Real * field_p = field.storage();
Real * normals_p = this->normals.storage();
Array<Real>::const_iterator< Vector<Real> > it_field = field.begin(dim);
Array<Real>::const_iterator< Vector<Real> > it_normal = this->normals.getArray().begin(dim);
Vector<Real> rfv(dim);
UInt nb_contact_nodes = this->getNbContactNodes();
for (UInt n=0; n<nb_contact_nodes; ++n) {
// nodes
UInt slave = this->slaves(n);
UInt master = this->masters(n);
// relative field vector (slave - master)
rfv = it_field[slave];
rfv -= it_field[master];
// length of normal projection of relative field
const Vector<Real> & normal_v = it_normal[n];
rel_normal_field.push_back(rfv.dot(normal_v));
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
Int NTNContact::getNodeIndex(UInt node) const {
AKANTU_DEBUG_IN();
Int slave_i = NTNBaseContact::getNodeIndex(node);
Int master_i = this->masters.find(node);
AKANTU_DEBUG_OUT();
return std::max(slave_i,master_i);
}
/* -------------------------------------------------------------------------- */
void NTNContact::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 << "NTNContact [" << std::endl;
NTNBaseContact::printself(stream, indent);
stream << space << " + masters : " << std::endl;
this->masters.printself(stream, indent + 2);
stream << space << " + lumped_boundary_mastres : " << std::endl;
this->lumped_boundary_masters.printself(stream, indent + 2);
stream << space << "]" << std::endl;
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::syncArrays(SyncChoice sync_choice) {
AKANTU_DEBUG_IN();
NTNBaseContact::syncArrays(sync_choice);
this->masters.syncElements(sync_choice);
this->lumped_boundary_masters.syncElements(sync_choice);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void NTNContact::addDumpFieldToDumper(const std::string & dumper_name,
const std::string & field_id) {
AKANTU_DEBUG_IN();
/*
#ifdef AKANTU_USE_IOHELPER
const Array<UInt> & nodal_filter = this->slaves.getArray();
#define ADD_FIELD(field_id, field, type) \
internalAddDumpFieldToDumper(dumper_name, \
field_id, \
new DumperIOHelper::NodalField< type, true, \
Array<type>, \
Array<UInt> >(field, 0, 0, &nodal_filter))
*/
if(field_id == "lumped_boundary_master") {
internalAddDumpFieldToDumper(dumper_name,
field_id,
new DumperIOHelper::NodalField<Real>(this->lumped_boundary_masters.getArray()));
}
else {
NTNBaseContact::addDumpFieldToDumper(dumper_name, field_id);
}
/*
#undef ADD_FIELD
#endif
*/
AKANTU_DEBUG_OUT();
}
__END_SIMTOOLS__

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