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ntn_contact.cc
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			/**
			* @file ntn_contact.cc
			*
			* @author David Simon Kammer <david.kammer@epfl.ch>
			*
			*
			* @brief implementation of ntn_contact
			*
			* @section LICENSE
			*
			* Copyright (©) 2010-2012, 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne)
			* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
			*
			*/

			/* -------------------------------------------------------------------------- */
			// simtools
			#include "ntn_contact.hh"
			#include "dumper_text.hh"
			#include "dumper_nodal_field.hh"

			__BEGIN_AKANTU__

			/* -------------------------------------------------------------------------- */
			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) {
			// compute the normals
			Array<Real> quad_normals(0,dim);
			boundary_fem.computeNormalsOnIntegrationPoints(cur_pos, quad_normals, it, gt);

			UInt nb_quad_points = boundary_fem.getNbIntegrationPoints(it, gt);

			// new version: compute normals only based on master elements (and not all boundary elements)
			// -------------------------------------------------------------------------------------

			UInt nb_nodes_per_element = mesh.getNbNodesPerElement(*it);
			const Array<UInt> & connectivity = mesh.getConnectivity(it, gt);

			Array<UInt>::const_iterator<UInt> elem_it = (this->master_elements)(it, gt).begin();
			Array<UInt>::const_iterator<UInt> elem_it_end = (this->master_elements)(it, gt).end();
			// loop over contact nodes
			for (; elem_it != elem_it_end; ++elem_it) {
			for (UInt q=0; q<nb_nodes_per_element; ++q) {
			UInt node = connectivity(*elem_it,q);
			UInt node_index = this->masters.find(node);
			AKANTU_DEBUG_ASSERT(node_index != UInt(-1),
			"Could not find node " << node
			<< " in the array!");

			for (UInt q=0; q<nb_quad_points; ++q) {
			// add quad normal to master normal
			for (UInt d=0; d<dim; ++d) {
			this->normals(node_index,d) += quad_normals((elem_it)nb_quad_points + q, d);
			}
			}
			}
			}
			// -------------------------------------------------------------------------------------

			/*
			// get elements connected to each node
			CSR<UInt> node_to_element;
			MeshUtils::buildNode2ElementsElementTypeMap(mesh, node_to_element, 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 = Vector<Real>(it_field[slave]);
			rfv -= Vector<Real>(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 = Vector<Real>(it_field[slave]);
			rfv -= Vector<Real>(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 dumper::NodalField<Real>(this->lumped_boundary_masters.getArray()));
			}
			else {
			NTNBaseContact::addDumpFieldToDumper(dumper_name, field_id);
			}

			/*
			#undef ADD_FIELD
			#endif
			*/

			AKANTU_DEBUG_OUT();
			}

			__END_AKANTU__

rAKA/extra_packages/traction-at-split-node-contact/src/ntn_contact/ntn_contact.cc5d56e862d8fcfeatures/friction_examp…

ntn_contact.ccView Options

rAKA/extra_packages/traction-at-split-node-contact/src/ntn_contact/ntn_contact.cc
5d56e862d8fcfeatures/friction_examp…

ntn_contact.cc
View Options