contact_mechanics_model.cc
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Created: Sun, Apr 28, 02:30

contact_mechanics_model.cc
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	/**
	* @file contact_mechanics_model.cc
	*
	* @author Mohit Pundir <mohit.pundir@epfl.ch>
	*
	* @date creation: Thu Feb 21 2013
	* @date last modification: Wed Jul 28 2021
	*
	* @brief Contact mechanics model
	*
	*
	* @section LICENSE
	*
	* Copyright (©) 2014-2021 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/>.
	*
	*/

	/* -------------------------------------------------------------------------- */
	#include "contact_mechanics_model.hh"
	#include "boundary_condition_functor.hh"
	#include "dumpable_inline_impl.hh"
	#include "group_manager_inline_impl.hh"
	#include "integrator_gauss.hh"
	#include "shape_lagrange.hh"
	/* -------------------------------------------------------------------------- */
	#include "dumper_iohelper_paraview.hh"
	/* -------------------------------------------------------------------------- */
	#include <algorithm>
	/* -------------------------------------------------------------------------- */

	namespace akantu {

	/* -------------------------------------------------------------------------- */
	ContactMechanicsModel::ContactMechanicsModel(
	Mesh & mesh, UInt dim, const ID & id,
	std::shared_ptr<DOFManager> dof_manager, const ModelType model_type)
	: Model(mesh, model_type, dof_manager, dim, id) {

	AKANTU_DEBUG_IN();

	this->registerFEEngineObject<MyFEEngineType>("ContactMechanicsModel", mesh,
	Model::spatial_dimension);
	this->mesh.registerDumper<DumperParaview>("contact_mechanics", id, true);
	this->mesh.addDumpMeshToDumper("contact_mechanics", mesh,
	Model::spatial_dimension - 1, _not_ghost,
	_ek_regular);

	this->registerDataAccessor(*this);

	this->detector =
	std::make_unique<ContactDetector>(this->mesh, id + ":contact_detector");

	registerFEEngineObject<MyFEEngineType>("ContactFacetsFEEngine", mesh,
	Model::spatial_dimension - 1);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	ContactMechanicsModel::~ContactMechanicsModel() = default;

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::initFullImpl(const ModelOptions & options) {

	Model::initFullImpl(options);

	// initalize the resolutions
	if (not this->parser.getLastParsedFile().empty()) {
	this->instantiateResolutions();
	this->initResolutions();
	}

	this->initBC(this, displacement, displacement_increment, external_force);
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::instantiateResolutions() {
	ParserSection model_section;
	bool is_empty;
	std::tie(model_section, is_empty) = this->getParserSection();

	if (not is_empty) {
	auto model_resolutions =
	model_section.getSubSections(ParserType::_contact_resolution);
	for (const auto & section : model_resolutions) {
	this->registerNewResolution(section);
	}
	}

	auto sub_sections =
	this->parser.getSubSections(ParserType::_contact_resolution);
	for (const auto & section : sub_sections) {
	this->registerNewResolution(section);
	}

	if (resolutions.empty()) {
	AKANTU_EXCEPTION("No contact resolutions where instantiated for the model"
	<< getID());
	}
	are_resolutions_instantiated = true;
	}

	/* -------------------------------------------------------------------------- */
	Resolution &
	ContactMechanicsModel::registerNewResolution(const ParserSection & section) {
	std::string res_name;
	std::string res_type = section.getName();
	std::string opt_param = section.getOption();

	try {
	std::string tmp = section.getParameter("name");
	res_name = tmp; /** this can seem weird, but there is an ambiguous operator
	* overload that i couldn't solve. @todo remove the
	* weirdness of this code
	*/
	} catch (debug::Exception &) {
	AKANTU_ERROR("A contact resolution of type \'"
	<< res_type
	<< "\' in the input file has been defined without a name!");
	}
	Resolution & res = this->registerNewResolution(res_name, res_type, opt_param);

	res.parseSection(section);

	return res;
	}

	/* -------------------------------------------------------------------------- */
	Resolution & ContactMechanicsModel::registerNewResolution(
	const ID & res_name, const ID & res_type, const ID & opt_param) {
	AKANTU_DEBUG_ASSERT(resolutions_names_to_id.find(res_name) ==
	resolutions_names_to_id.end(),
	"A resolution with this name '"
	<< res_name << "' has already been registered. "
	<< "Please use unique names for resolutions");

	UInt res_count = resolutions.size();
	resolutions_names_to_id[res_name] = res_count;

	std::stringstream sstr_res;
	sstr_res << this->id << ":" << res_count << ":" << res_type;
	ID res_id = sstr_res.str();

	std::unique_ptr<Resolution> resolution =
	ResolutionFactory::getInstance().allocate(res_type, spatial_dimension,
	opt_param, *this, res_id);

	resolutions.push_back(std::move(resolution));

	return *(resolutions.back());
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::initResolutions() {
	AKANTU_DEBUG_ASSERT(resolutions.size() != 0,
	"No resolutions to initialize !");

	if (!are_resolutions_instantiated) {
	instantiateResolutions();
	}
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::initModel() {

	AKANTU_DEBUG_IN();

	getFEEngine("ContactMechanicsModel").initShapeFunctions(_not_ghost);
	getFEEngine("ContactMechanicsModel").initShapeFunctions(_ghost);

	getFEEngine("ContactFacetsFEEngine").initShapeFunctions(_not_ghost);
	getFEEngine("ContactFacetsFEEngine").initShapeFunctions(_ghost);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	FEEngine & ContactMechanicsModel::getFEEngineBoundary(const ID & name) {
	return dynamic_cast<FEEngine &>(
	getFEEngineClassBoundary<MyFEEngineType>(name));
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::initSolver(
	TimeStepSolverType /time_step_solver_type/,
	NonLinearSolverType /unused/) {

	// for alloc type of solvers
	this->allocNodalField(this->displacement, spatial_dimension, "displacement");
	this->allocNodalField(this->displacement_increment, spatial_dimension,
	"displacement_increment");
	this->allocNodalField(this->internal_force, spatial_dimension,
	"internal_force");
	this->allocNodalField(this->external_force, spatial_dimension,
	"external_force");
	this->allocNodalField(this->normal_force, spatial_dimension, "normal_force");
	this->allocNodalField(this->tangential_force, spatial_dimension,
	"tangential_force");

	this->allocNodalField(this->gaps, 1, "gaps");
	this->allocNodalField(this->nodal_area, 1, "areas");
	this->allocNodalField(this->blocked_dofs, 1, "blocked_dofs");
	this->allocNodalField(this->contact_state, 1, "contact_state");
	this->allocNodalField(this->previous_master_elements, 1,
	"previous_master_elements");

	this->allocNodalField(this->normals, spatial_dimension, "normals");

	auto surface_dimension = spatial_dimension - 1;
	this->allocNodalField(this->tangents, surface_dimension * spatial_dimension,
	"tangents");
	this->allocNodalField(this->projections, surface_dimension, "projections");
	this->allocNodalField(this->previous_projections, surface_dimension,
	"previous_projections");
	this->allocNodalField(this->previous_tangents,
	surface_dimension * spatial_dimension,
	"previous_tangents");
	this->allocNodalField(this->tangential_tractions, surface_dimension,
	"tangential_tractions");
	this->allocNodalField(this->previous_tangential_tractions, surface_dimension,
	"previous_tangential_tractions");

	// todo register multipliers as dofs for lagrange multipliers
	}

	/* -------------------------------------------------------------------------- */
	std::tuple<ID, TimeStepSolverType>
	ContactMechanicsModel::getDefaultSolverID(const AnalysisMethod & method) {
	switch (method) {
	case _explicit_lumped_mass: {
	return std::make_tuple("explicit_lumped",
	TimeStepSolverType::_dynamic_lumped);
	}
	case _explicit_consistent_mass: {
	return std::make_tuple("explicit", TimeStepSolverType::_dynamic);
	}
	case _static: {
	return std::make_tuple("static", TimeStepSolverType::_static);
	}
	case _implicit_dynamic: {
	return std::make_tuple("implicit", TimeStepSolverType::_dynamic);
	}
	default:
	return std::make_tuple("unknown", TimeStepSolverType::_not_defined);
	}
	}

	/* -------------------------------------------------------------------------- */
	ModelSolverOptions ContactMechanicsModel::getDefaultSolverOptions(
	const TimeStepSolverType & type) const {
	ModelSolverOptions options;

	switch (type) {
	case TimeStepSolverType::_dynamic: {
	options.non_linear_solver_type = NonLinearSolverType::_lumped;
	options.integration_scheme_type["displacement"] =
	IntegrationSchemeType::_central_difference;
	options.solution_type["displacement"] = IntegrationScheme::_acceleration;
	break;
	}
	case TimeStepSolverType::_dynamic_lumped: {
	options.non_linear_solver_type = NonLinearSolverType::_lumped;
	options.integration_scheme_type["displacement"] =
	IntegrationSchemeType::_central_difference;
	options.solution_type["displacement"] = IntegrationScheme::_acceleration;
	break;
	}
	case TimeStepSolverType::_static: {
	options.non_linear_solver_type =
	NonLinearSolverType::_newton_raphson_contact;
	options.integration_scheme_type["displacement"] =
	IntegrationSchemeType::_pseudo_time;
	options.solution_type["displacement"] = IntegrationScheme::_not_defined;
	break;
	}
	default:
	AKANTU_EXCEPTION(type << " is not a valid time step solver type");
	break;
	}

	return options;
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::assembleResidual() {
	AKANTU_DEBUG_IN();

	/* ------------------------------------------------------------------------ */
	// computes the internal forces
	this->assembleInternalForces();

	/* ------------------------------------------------------------------------ */
	this->getDOFManager().assembleToResidual("displacement",
	*this->internal_force, 1);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::assembleInternalForces() {
	AKANTU_DEBUG_IN();

	AKANTU_DEBUG_INFO("Assemble the contact forces");

	UInt nb_nodes = mesh.getNbNodes();
	this->internal_force->clear();
	this->normal_force->clear();
	this->tangential_force->clear();

	internal_force->resize(nb_nodes, 0.);
	normal_force->resize(nb_nodes, 0.);
	tangential_force->resize(nb_nodes, 0.);

	// assemble the forces due to contact
	auto assemble = [&](auto && ghost_type) {
	for (auto & resolution : resolutions) {
	resolution->assembleInternalForces(ghost_type);
	}
	};

	AKANTU_DEBUG_INFO("Assemble residual for local elements");
	assemble(_not_ghost);

	// assemble the stresses due to ghost elements
	// AKANTU_DEBUG_INFO("Assemble residual for ghost elements");
	// assemble(_ghost);

	AKANTU_DEBUG_OUT();
	}
	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::search() {

	// save the previous state
	this->savePreviousState();

	contact_elements.clear();

	// this needs to be resized if cohesive elements are added
	UInt nb_nodes = mesh.getNbNodes();

	auto resize_arrays = [&](auto & internal_array) {
	internal_array->resize(nb_nodes);
	internal_array->zero();
	};

	resize_arrays(gaps);
	resize_arrays(normals);
	resize_arrays(tangents);
	resize_arrays(projections);
	resize_arrays(tangential_tractions);
	resize_arrays(contact_state);
	resize_arrays(nodal_area);
	resize_arrays(external_force);

	this->detector->search(contact_elements, gaps, normals, *tangents,
	*projections);

	// interpenetration value must be positive for contact mechanics
	// model to work by default the gap value from detector is negative
	std::for_each((gaps).begin(), (gaps).end(), [](Real & gap) { gap *= -1.; });

	if (!contact_elements.empty()) {
	this->computeNodalAreas();
	}
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::savePreviousState() {

	AKANTU_DEBUG_IN();

	// saving previous natural projections
	(previous_projections).copy(projections);

	// saving previous tangents
	(previous_tangents).copy(tangents);

	// saving previous tangential traction
	(previous_tangential_tractions).copy(tangential_tractions);

	previous_master_elements->clear();
	previous_master_elements->resize(projections->size());
	previous_master_elements->set(ElementNull);
	for (auto & element : contact_elements) {
	(*previous_master_elements)[element.slave] = element.master;
	}

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::computeNodalAreas(GhostType ghost_type) {

	UInt nb_nodes = mesh.getNbNodes();

	nodal_area->resize(nb_nodes);
	nodal_area->zero();

	external_force->resize(nb_nodes);
	external_force->zero();

	auto & fem_boundary =
	getFEEngineClassBoundary<MyFEEngineType>("ContactMechanicsModel");

	fem_boundary.initShapeFunctions(getPositions(), _not_ghost);
	fem_boundary.initShapeFunctions(getPositions(), _ghost);

	fem_boundary.computeNormalsOnIntegrationPoints(_not_ghost);
	fem_boundary.computeNormalsOnIntegrationPoints(_ghost);

	IntegrationPoint quad_point;
	quad_point.ghost_type = ghost_type;

	auto & group = mesh.getElementGroup("contact_surface");
	UInt nb_degree_of_freedom = external_force->getNbComponent();

	for (auto && type : group.elementTypes(spatial_dimension - 1, ghost_type)) {
	const auto & element_ids = group.getElements(type, ghost_type);

	UInt nb_quad_points = fem_boundary.getNbIntegrationPoints(type, ghost_type);
	UInt nb_elements = element_ids.size();

	UInt nb_nodes_per_element = mesh.getNbNodesPerElement(type);

	Array<Real> dual_before_integ(nb_elements * nb_quad_points,
	nb_degree_of_freedom, 0.);
	Array<Real> quad_coords(nb_elements * nb_quad_points, spatial_dimension);

	const auto & normals_on_quad =
	fem_boundary.getNormalsOnIntegrationPoints(type, ghost_type);

	auto normals_begin = normals_on_quad.begin(spatial_dimension);
	decltype(normals_begin) normals_iter;
	auto quad_coords_iter = quad_coords.begin(spatial_dimension);
	auto dual_iter = dual_before_integ.begin(nb_degree_of_freedom);

	quad_point.type = type;

	Element subelement;
	subelement.type = type;
	subelement.ghost_type = ghost_type;
	for (auto el : element_ids) {
	subelement.element = el;
	const auto & element_to_subelement =
	mesh.getElementToSubelement(type)(el);

	Vector<Real> outside(spatial_dimension);
	mesh.getBarycenter(subelement, outside);

	Vector<Real> inside(spatial_dimension);
	if (mesh.isMeshFacets()) {
	mesh.getMeshParent().getBarycenter(element_to_subelement[0], inside);
	} else {
	mesh.getBarycenter(element_to_subelement[0], inside);
	}

	Vector<Real> inside_to_outside(spatial_dimension);
	inside_to_outside = outside - inside;

	normals_iter = normals_begin + el * nb_quad_points;

	quad_point.element = el;
	for (auto q : arange(nb_quad_points)) {
	quad_point.num_point = q;
	auto ddot = inside_to_outside.dot(*normals_iter);
	Vector<Real> normal(*normals_iter);
	if (ddot < 0) {
	normal *= -1.0;
	}

	(*dual_iter)
	.mul<false>(Matrix<Real>::eye(spatial_dimension, 1), normal);
	++dual_iter;
	++quad_coords_iter;
	++normals_iter;
	}
	}

	Array<Real> dual_by_shapes(nb_elements * nb_quad_points,
	nb_degree_of_freedom * nb_nodes_per_element);

	fem_boundary.computeNtb(dual_before_integ, dual_by_shapes, type, ghost_type,
	element_ids);

	Array<Real> dual_by_shapes_integ(nb_elements, nb_degree_of_freedom *
	nb_nodes_per_element);
	fem_boundary.integrate(dual_by_shapes, dual_by_shapes_integ,
	nb_degree_of_freedom * nb_nodes_per_element, type,
	ghost_type, element_ids);

	this->getDOFManager().assembleElementalArrayLocalArray(
	dual_by_shapes_integ, *external_force, type, ghost_type, 1.,
	element_ids);
	}

	for (auto && tuple :
	zip(nodal_area, make_view(external_force, spatial_dimension))) {

	auto & area = std::get<0>(tuple);
	Vector<Real> force(std::get<1>(tuple));
	area = force.norm();
	}

	this->external_force->clear();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::printself(std::ostream & stream, int indent) const {
	std::string space(indent, AKANTU_INDENT);

	stream << space << "Contact Mechanics Model [" << std::endl;
	stream << space << " + id : " << id << std::endl;
	stream << space << " + spatial dimension : " << Model::spatial_dimension
	<< std::endl;
	stream << space << " + fem [" << std::endl;
	getFEEngine().printself(stream, indent + 2);
	stream << space << AKANTU_INDENT << "]" << std::endl;

	stream << space << " + resolutions [" << std::endl;
	for (const auto & resolution : resolutions) {
	resolution->printself(stream, indent + 1);
	}
	stream << space << AKANTU_INDENT << "]" << std::endl;

	stream << space << "]" << std::endl;
	}

	/* -------------------------------------------------------------------------- */
	MatrixType ContactMechanicsModel::getMatrixType(const ID & matrix_id) const {
	if (matrix_id == "K") {
	return _symmetric;
	}

	return _mt_not_defined;
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::assembleMatrix(const ID & matrix_id) {
	if (matrix_id == "K") {
	this->assembleStiffnessMatrix();
	}
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::assembleStiffnessMatrix() {
	AKANTU_DEBUG_INFO("Assemble the new stiffness matrix");

	if (!this->getDOFManager().hasMatrix("K")) {
	this->getDOFManager().getNewMatrix("K", getMatrixType("K"));
	}

	for (auto & resolution : resolutions) {
	resolution->assembleStiffnessMatrix(_not_ghost);
	}
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::assembleLumpedMatrix(const ID & /matrix_id/) {
	AKANTU_TO_IMPLEMENT();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::beforeSolveStep() {
	for (auto & resolution : resolutions) {
	resolution->beforeSolveStep();
	}
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::afterSolveStep(bool converged) {
	for (auto & resolution : resolutions) {
	resolution->afterSolveStep(converged);
	}
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field>
	ContactMechanicsModel::createNodalFieldBool(const std::string & /unused/,
	const std::string & /unused/,
	bool /unused/) {
	return nullptr;
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field>
	ContactMechanicsModel::createNodalFieldReal(const std::string & field_name,
	const std::string & group_name,
	bool padding_flag) {
	std::map<std::string, Array<Real> *> real_nodal_fields;
	real_nodal_fields["contact_force"] = this->internal_force.get();
	real_nodal_fields["normal_force"] = this->normal_force.get();
	real_nodal_fields["tangential_force"] = this->tangential_force.get();
	real_nodal_fields["blocked_dofs"] = this->blocked_dofs.get();
	real_nodal_fields["normals"] = this->normals.get();
	real_nodal_fields["tangents"] = this->tangents.get();
	real_nodal_fields["gaps"] = this->gaps.get();
	real_nodal_fields["areas"] = this->nodal_area.get();
	real_nodal_fields["tangential_traction"] = this->tangential_tractions.get();

	std::shared_ptr<dumpers::Field> field;
	if (padding_flag) {
	field = this->mesh.createNodalField(real_nodal_fields[field_name],
	group_name, 3);
	} else {
	field =
	this->mesh.createNodalField(real_nodal_fields[field_name], group_name);
	}
	return field;
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field>
	ContactMechanicsModel::createNodalFieldUInt(const std::string & field_name,
	const std::string & group_name,
	bool /padding_flag/) {
	std::shared_ptr<dumpers::Field> field;
	if (field_name == "contact_state") {
	auto && func =
	std::make_unique<dumpers::ComputeUIntFromEnum<ContactState>>();
	field = mesh.createNodalField(this->contact_state.get(), group_name);
	field =
	dumpers::FieldComputeProxy::createFieldCompute(field, std::move(func));
	}
	return field;
	}

	/* -------------------------------------------------------------------------- */
	UInt ContactMechanicsModel::getNbData(
	const Array<Element> & elements, const SynchronizationTag & /tag/) const {
	AKANTU_DEBUG_IN();

	UInt size = 0;
	UInt nb_nodes_per_element = 0;

	for (const Element & el : elements) {
	nb_nodes_per_element += Mesh::getNbNodesPerElement(el.type);
	}

	AKANTU_DEBUG_OUT();
	return size;
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::packData(CommunicationBuffer & /buffer/,
	const Array<Element> & /elements/,
	const SynchronizationTag & /tag/) const {
	AKANTU_DEBUG_IN();

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::unpackData(CommunicationBuffer & /buffer/,
	const Array<Element> & /elements/,
	const SynchronizationTag & /tag/) {
	AKANTU_DEBUG_IN();

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	UInt ContactMechanicsModel::getNbData(
	const Array<UInt> & dofs, const SynchronizationTag & /tag/) const {
	AKANTU_DEBUG_IN();

	UInt size = 0;

	AKANTU_DEBUG_OUT();
	return size * dofs.size();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::packData(CommunicationBuffer & /buffer/,
	const Array<UInt> & /dofs/,
	const SynchronizationTag & /tag/) const {
	AKANTU_DEBUG_IN();

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void ContactMechanicsModel::unpackData(CommunicationBuffer & /buffer/,
	const Array<UInt> & /dofs/,
	const SynchronizationTag & /tag/) {
	AKANTU_DEBUG_IN();

	AKANTU_DEBUG_OUT();
	}

	} // namespace akantu

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