structural_mechanics_model.cc
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structural_mechanics_model.cc
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	/**
	* @file structural_mechanics_model.cc
	*
	* @author Fabian Barras <fabian.barras@epfl.ch>
	* @author Lucas Frerot <lucas.frerot@epfl.ch>
	* @author Sébastien Hartmann <sebastien.hartmann@epfl.ch>
	* @author Nicolas Richart <nicolas.richart@epfl.ch>
	* @author Damien Spielmann <damien.spielmann@epfl.ch>
	*
	* @date creation: Fri Jul 15 2011
	* @date last modification: Mon Mar 15 2021
	*
	* @brief Model implementation for Structural Mechanics elements
	*
	*
	* @section LICENSE
	*
	* Copyright (©) 2010-2021 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 "structural_mechanics_model.hh"
	#include "dof_manager.hh"
	#include "integrator_gauss.hh"
	#include "mesh.hh"
	#include "shape_structural.hh"
	#include "sparse_matrix.hh"
	#include "time_step_solver.hh"
	/* -------------------------------------------------------------------------- */
	#ifdef AKANTU_USE_IOHELPER
	#include "dumpable_inline_impl.hh"
	#include "dumper_elemental_field.hh"
	#include "dumper_internal_material_field.hh"
	#include "dumper_iohelper_paraview.hh"
	#include "group_manager_inline_impl.hh"
	#endif
	/* -------------------------------------------------------------------------- */
	#include "structural_element_bernoulli_beam_2.hh"
	#include "structural_element_bernoulli_beam_3.hh"
	#include "structural_element_kirchhoff_shell.hh"
	/* -------------------------------------------------------------------------- */
	//#include "structural_mechanics_model_inline_impl.hh"
	/* -------------------------------------------------------------------------- */

	namespace akantu {

	/* -------------------------------------------------------------------------- */
	inline UInt StructuralMechanicsModel::getNbDegreeOfFreedom(ElementType type) {
	UInt ndof = 0;
	#define GET_(type) ndof = ElementClass<type>::getNbDegreeOfFreedom()
	AKANTU_BOOST_KIND_ELEMENT_SWITCH(GET_, _ek_structural);
	#undef GET_

	return ndof;
	}

	/* -------------------------------------------------------------------------- */
	StructuralMechanicsModel::StructuralMechanicsModel(Mesh & mesh, UInt dim,
	const ID & id)
	: Model(mesh, ModelType::_structural_mechanics_model, dim, id), f_m2a(1.0),
	stress("stress", id), element_material("element_material", id),
	set_ID("beam sets", id) {
	AKANTU_DEBUG_IN();

	registerFEEngineObject<MyFEEngineType>("StructuralMechanicsFEEngine", mesh,
	spatial_dimension);

	if (spatial_dimension == 2) {
	nb_degree_of_freedom = 3;
	} else if (spatial_dimension == 3) {
	nb_degree_of_freedom = 6;
	} else {
	AKANTU_TO_IMPLEMENT();
	}

	#ifdef AKANTU_USE_IOHELPER
	this->mesh.registerDumper<DumperParaview>("structural_mechanics_model", id,
	true);
	#endif
	this->mesh.addDumpMesh(mesh, spatial_dimension, _not_ghost, _ek_structural);

	this->initDOFManager();

	this->dumper_default_element_kind = _ek_structural;

	mesh.getElementalData<Real>("extra_normal")
	.initialize(mesh, _element_kind = _ek_structural,
	_nb_component = spatial_dimension, _with_nb_element = true,
	_default_value = 0.);

	AKANTU_DEBUG_OUT();
	}

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

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::initFullImpl(const ModelOptions & options) {
	Model::initFullImpl(options);

	// Initializing stresses
	ElementTypeMap<UInt> stress_components;

	/// TODO this is ugly af, maybe add a function to FEEngine
	for (auto && type : mesh.elementTypes(_spatial_dimension = _all_dimensions,
	_element_kind = _ek_structural)) {
	UInt nb_components = 0;

	// Getting number of components for each element type
	#define GET_(type) nb_components = ElementClass<type>::getNbStressComponents()
	AKANTU_BOOST_STRUCTURAL_ELEMENT_SWITCH(GET_);
	#undef GET_

	stress_components(nb_components, type);
	}

	stress.initialize(
	getFEEngine(), _spatial_dimension = _all_dimensions,
	_element_kind = _ek_structural,
	_nb_component = [&stress_components](ElementType type,
	GhostType /unused/) -> UInt {
	return stress_components(type);
	});
	}

	/* -------------------------------------------------------------------------- */

	void StructuralMechanicsModel::initFEEngineBoundary() {
	/// TODO: this function should not be reimplemented
	/// we're just avoiding a call to Model::initFEEngineBoundary()
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::setTimeStep(Real time_step,
	const ID & solver_id) {
	Model::setTimeStep(time_step, solver_id);
	#if defined(AKANTU_USE_IOHELPER)
	this->mesh.getDumper().setTimeStep(time_step);
	#endif
	}

	/* -------------------------------------------------------------------------- */
	/* Initialisation */
	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::initSolver(
	TimeStepSolverType time_step_solver_type, NonLinearSolverType /unused/) {
	AKANTU_DEBUG_IN();

	this->allocNodalField(displacement_rotation, nb_degree_of_freedom,
	"displacement");
	this->allocNodalField(external_force, nb_degree_of_freedom, "external_force");
	this->allocNodalField(internal_force, nb_degree_of_freedom, "internal_force");
	this->allocNodalField(blocked_dofs, nb_degree_of_freedom, "blocked_dofs");

	auto & dof_manager = this->getDOFManager();

	if (not dof_manager.hasDOFs("displacement")) {
	dof_manager.registerDOFs("displacement", *displacement_rotation,
	_dst_nodal);
	dof_manager.registerBlockedDOFs("displacement", *this->blocked_dofs);
	}

	if (time_step_solver_type == TimeStepSolverType::_dynamic \|\|
	time_step_solver_type == TimeStepSolverType::_dynamic_lumped) {
	this->allocNodalField(velocity, nb_degree_of_freedom, "velocity");
	this->allocNodalField(acceleration, nb_degree_of_freedom, "acceleration");

	if (!dof_manager.hasDOFsDerivatives("displacement", 1)) {
	dof_manager.registerDOFsDerivative("displacement", 1, *this->velocity);
	dof_manager.registerDOFsDerivative("displacement", 2,
	*this->acceleration);
	}
	}

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::initModel() {
	element_material.initialize(mesh, _element_kind = _ek_structural,
	_default_value = 0, _with_nb_element = true);

	getFEEngine().initShapeFunctions(_not_ghost);
	getFEEngine().initShapeFunctions(_ghost);
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::assembleStiffnessMatrix() {
	AKANTU_DEBUG_IN();

	if (not need_to_reassemble_stiffness) {
	return;
	}

	if (not getDOFManager().hasMatrix("K")) {
	getDOFManager().getNewMatrix("K", getMatrixType("K"));
	}

	this->getDOFManager().zeroMatrix("K");

	for (const auto & type :
	mesh.elementTypes(spatial_dimension, _not_ghost, _ek_structural)) {
	#define ASSEMBLE_STIFFNESS_MATRIX(type) assembleStiffnessMatrix<type>();

	AKANTU_BOOST_STRUCTURAL_ELEMENT_SWITCH(ASSEMBLE_STIFFNESS_MATRIX);
	#undef ASSEMBLE_STIFFNESS_MATRIX
	}

	need_to_reassemble_stiffness = false;

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::computeStresses() {
	AKANTU_DEBUG_IN();

	for (const auto & type :
	mesh.elementTypes(spatial_dimension, _not_ghost, _ek_structural)) {
	#define COMPUTE_STRESS_ON_QUAD(type) computeStressOnQuad<type>();

	AKANTU_BOOST_STRUCTURAL_ELEMENT_SWITCH(COMPUTE_STRESS_ON_QUAD);
	#undef COMPUTE_STRESS_ON_QUAD
	}

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field> StructuralMechanicsModel::createNodalFieldBool(
	const std::string & field_name, const std::string & group_name,
	__attribute__((unused)) bool padding_flag) {

	std::map<std::string, Array<bool> *> uint_nodal_fields;
	uint_nodal_fields["blocked_dofs"] = blocked_dofs.get();

	return mesh.createNodalField(uint_nodal_fields[field_name], group_name);
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field>
	StructuralMechanicsModel::createNodalFieldReal(const std::string & field_name,
	const std::string & group_name,
	bool padding_flag) {

	UInt n;
	if (spatial_dimension == 2) {
	n = 2;
	} else {
	n = 3;
	}

	UInt padding_size = 0;
	if (padding_flag) {
	padding_size = 3;
	}

	if (field_name == "displacement") {
	return mesh.createStridedNodalField(displacement_rotation.get(), group_name,
	n, 0, padding_size);
	}

	if (field_name == "velocity") {
	return mesh.createStridedNodalField(velocity.get(), group_name, n, 0,
	padding_size);
	}

	if (field_name == "acceleration") {
	return mesh.createStridedNodalField(acceleration.get(), group_name, n, 0,
	padding_size);
	}

	if (field_name == "rotation") {
	return mesh.createStridedNodalField(displacement_rotation.get(), group_name,
	nb_degree_of_freedom - n, n,
	padding_size);
	}

	if (field_name == "force") {
	return mesh.createStridedNodalField(external_force.get(), group_name, n, 0,
	padding_size);
	}
	if (field_name == "external_force") {
	return mesh.createStridedNodalField(external_force.get(), group_name, n, 0,
	padding_size);
	}

	if (field_name == "momentum") {
	return mesh.createStridedNodalField(external_force.get(), group_name,
	nb_degree_of_freedom - n, n,
	padding_size);
	}

	if (field_name == "internal_force") {
	return mesh.createStridedNodalField(internal_force.get(), group_name, n, 0,
	padding_size);
	}

	if (field_name == "internal_momentum") {
	return mesh.createStridedNodalField(internal_force.get(), group_name,
	nb_degree_of_freedom - n, n,
	padding_size);
	}

	return nullptr;
	}

	/* -------------------------------------------------------------------------- */
	std::shared_ptr<dumpers::Field> StructuralMechanicsModel::createElementalField(
	const std::string & field_name, const std::string & group_name,
	bool /unused/, UInt spatial_dimension, ElementKind kind) {

	std::shared_ptr<dumpers::Field> field;

	if (field_name == "element_index_by_material") {
	field = mesh.createElementalField<UInt, Vector, dumpers::ElementalField>(
	field_name, group_name, spatial_dimension, kind);
	}
	if (field_name == "stress") {
	ElementTypeMap<UInt> nb_data_per_elem = this->mesh.getNbDataPerElem(stress);

	field = mesh.createElementalField<Real, dumpers::InternalMaterialField>(
	stress, group_name, this->spatial_dimension, kind, nb_data_per_elem);
	}

	return field;
	}

	/* -------------------------------------------------------------------------- */
	/* Virtual methods from SolverCallback */
	/* -------------------------------------------------------------------------- */
	/// get the type of matrix needed
	MatrixType StructuralMechanicsModel::getMatrixType(const ID & /id/) {
	return _symmetric;
	}

	/// callback to assemble a Matrix
	void StructuralMechanicsModel::assembleMatrix(const ID & id) {
	if (id == "K") {
	assembleStiffnessMatrix();
	} else if (id == "M") {
	assembleMassMatrix();
	}
	}

	/// callback to assemble a lumped Matrix
	void StructuralMechanicsModel::assembleLumpedMatrix(const ID & /id/) {}

	/// callback to assemble the residual StructuralMechanicsModel::(rhs)
	void StructuralMechanicsModel::assembleResidual() {
	AKANTU_DEBUG_IN();

	auto & dof_manager = getDOFManager();

	assembleInternalForce();

	dof_manager.assembleToResidual("displacement", *external_force, 1);
	dof_manager.assembleToResidual("displacement", *internal_force, 1);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::assembleResidual(const ID & residual_part) {
	AKANTU_DEBUG_IN();

	if ("external" == residual_part) {
	this->getDOFManager().assembleToResidual("displacement",
	*this->external_force, 1);
	AKANTU_DEBUG_OUT();
	return;
	}

	if ("internal" == residual_part) {
	this->assembleInternalForce();
	this->getDOFManager().assembleToResidual("displacement",
	*this->internal_force, 1);
	AKANTU_DEBUG_OUT();
	return;
	}

	AKANTU_CUSTOM_EXCEPTION(
	debug::SolverCallbackResidualPartUnknown(residual_part));

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	/* Virtual methods from Model */
	/* -------------------------------------------------------------------------- */
	/// get some default values for derived classes
	std::tuple<ID, TimeStepSolverType>
	StructuralMechanicsModel::getDefaultSolverID(const AnalysisMethod & method) {
	switch (method) {
	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 StructuralMechanicsModel::getDefaultSolverOptions(
	const TimeStepSolverType & type) const {
	ModelSolverOptions options;

	switch (type) {
	case TimeStepSolverType::_static: {
	options.non_linear_solver_type = NonLinearSolverType::_newton_raphson;
	options.integration_scheme_type["displacement"] =
	IntegrationSchemeType::_pseudo_time;
	options.solution_type["displacement"] = IntegrationScheme::_not_defined;
	break;
	}
	case TimeStepSolverType::_dynamic: {
	options.non_linear_solver_type = NonLinearSolverType::_newton_raphson;
	options.integration_scheme_type["displacement"] =
	IntegrationSchemeType::_trapezoidal_rule_2;
	options.solution_type["displacement"] = IntegrationScheme::_displacement;
	break;
	}
	default:
	AKANTU_EXCEPTION(type << " is not a valid time step solver type");
	}

	return options;
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::assembleInternalForce() {
	internal_force->zero();
	computeStresses();

	for (auto type : mesh.elementTypes(_spatial_dimension = _all_dimensions,
	_element_kind = _ek_structural)) {
	assembleInternalForce(type, _not_ghost);
	// assembleInternalForce(type, _ghost);
	}
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::assembleInternalForce(ElementType type,
	GhostType gt) {
	auto & fem = getFEEngine();
	auto & sigma = stress(type, gt);
	auto ndof = getNbDegreeOfFreedom(type);
	auto nb_nodes = mesh.getNbNodesPerElement(type);
	auto ndof_per_elem = ndof * nb_nodes;

	Array<Real> BtSigma(fem.getNbIntegrationPoints(type) *
	mesh.getNbElement(type),
	ndof_per_elem, "BtSigma");
	fem.computeBtD(sigma, BtSigma, type, gt);

	Array<Real> intBtSigma(0, ndof_per_elem, "intBtSigma");
	fem.integrate(BtSigma, intBtSigma, ndof_per_elem, type, gt);

	getDOFManager().assembleElementalArrayLocalArray(intBtSigma, *internal_force,
	type, gt, -1.);
	}

	/* -------------------------------------------------------------------------- */
	Real StructuralMechanicsModel::getKineticEnergy() {
	if (not this->getDOFManager().hasMatrix("M")) {
	return 0.;
	}

	Real ekin = 0.;
	UInt nb_nodes = mesh.getNbNodes();

	Array<Real> Mv(nb_nodes, nb_degree_of_freedom);
	this->getDOFManager().assembleMatMulVectToArray("displacement", "M",
	*this->velocity, Mv);

	for (auto && data : zip(arange(nb_nodes), make_view(Mv, nb_degree_of_freedom),
	make_view(*this->velocity, nb_degree_of_freedom))) {
	ekin += std::get<2>(data).dot(std::get<1>(data)) *
	static_cast<Real>(mesh.isLocalOrMasterNode(std::get<0>(data)));
	}

	mesh.getCommunicator().allReduce(ekin, SynchronizerOperation::_sum);

	return ekin / 2.;
	}

	/* -------------------------------------------------------------------------- */
	Real StructuralMechanicsModel::getPotentialEnergy() {
	Real epot = 0.;
	UInt nb_nodes = mesh.getNbNodes();

	Array<Real> Ku(nb_nodes, nb_degree_of_freedom);
	this->getDOFManager().assembleMatMulVectToArray(
	"displacement", "K", *this->displacement_rotation, Ku);

	for (auto && data :
	zip(arange(nb_nodes), make_view(Ku, nb_degree_of_freedom),
	make_view(*this->displacement_rotation, nb_degree_of_freedom))) {
	epot += std::get<2>(data).dot(std::get<1>(data)) *
	static_cast<Real>(mesh.isLocalOrMasterNode(std::get<0>(data)));
	}

	mesh.getCommunicator().allReduce(epot, SynchronizerOperation::_sum);

	return epot / 2.;
	}

	/* -------------------------------------------------------------------------- */
	Real StructuralMechanicsModel::getEnergy(const ID & energy) {
	if (energy == "kinetic") {
	return getKineticEnergy();
	}

	if (energy == "potential") {
	return getPotentialEnergy();
	}

	return 0;
	}

	/* -------------------------------------------------------------------------- */
	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::computeForcesByLocalTractionArray(
	const Array<Real> & tractions, ElementType type) {
	AKANTU_DEBUG_IN();

	auto nb_element = getFEEngine().getMesh().getNbElement(type);
	auto nb_nodes_per_element =
	getFEEngine().getMesh().getNbNodesPerElement(type);
	auto nb_quad = getFEEngine().getNbIntegrationPoints(type);

	// check dimension match
	AKANTU_DEBUG_ASSERT(
	Mesh::getSpatialDimension(type) == getFEEngine().getElementDimension(),
	"element type dimension does not match the dimension of boundaries : "
	<< getFEEngine().getElementDimension()
	<< " != " << Mesh::getSpatialDimension(type));

	// check size of the vector
	AKANTU_DEBUG_ASSERT(
	tractions.size() == nb_quad * nb_element,
	"the size of the vector should be the total number of quadrature points");

	// check number of components
	AKANTU_DEBUG_ASSERT(tractions.getNbComponent() == nb_degree_of_freedom,
	"the number of components should be the spatial "
	"dimension of the problem");

	Array<Real> Ntbs(nb_element * nb_quad,
	nb_degree_of_freedom * nb_nodes_per_element);

	auto & fem = getFEEngine();
	fem.computeNtb(tractions, Ntbs, type);

	// allocate the vector that will contain the integrated values
	auto name = id + std::to_string(type) + ":integral_boundary";
	Array<Real> int_funct(nb_element, nb_degree_of_freedom * nb_nodes_per_element,
	name);

	// do the integration
	getFEEngine().integrate(Ntbs, int_funct,
	nb_degree_of_freedom * nb_nodes_per_element, type);

	// assemble the result into force vector
	getDOFManager().assembleElementalArrayLocalArray(int_funct, *external_force,
	type, _not_ghost, 1);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::computeForcesByGlobalTractionArray(
	const Array<Real> & traction_global, ElementType type) {
	AKANTU_DEBUG_IN();

	UInt nb_element = mesh.getNbElement(type);
	UInt nb_quad = getFEEngine().getNbIntegrationPoints(type);

	Array<Real> traction_local(nb_element * nb_quad, nb_degree_of_freedom,
	id + ":structuralmechanics:imposed_linear_load");

	auto R_it = getFEEngineClass<MyFEEngineType>()
	.getShapeFunctions()
	.getRotations(type)
	.begin(nb_degree_of_freedom, nb_degree_of_freedom);

	auto Te_it = traction_global.begin(nb_degree_of_freedom);
	auto te_it = traction_local.begin(nb_degree_of_freedom);

	for (UInt e = 0; e < nb_element; ++e, ++R_it) {
	for (UInt q = 0; q < nb_quad; ++q, ++Te_it, ++te_it) {
	// turn the traction in the local referential
	te_it->template mul<false>(R_it, Te_it);
	}
	}

	computeForcesByLocalTractionArray(traction_local, type);

	AKANTU_DEBUG_OUT();
	}

	/* -------------------------------------------------------------------------- */
	void StructuralMechanicsModel::afterSolveStep(bool converged) {
	if (converged) {
	assembleInternalForce();
	}
	}

	} // namespace akantu

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