structural_mechanics_model.hh
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Created: Wed, Dec 11, 16:52

structural_mechanics_model.hh
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	/**
	* @file structural_mechanics_model.hh
	*
	* @author Fabian Barras <fabian.barras@epfl.ch>
	* @author Lucas Frerot <lucas.frerot@epfl.ch>
	* @author Sébastien Hartmann <sebastien.hartmann@epfl.ch>
	* @author Philip Mueller <philip.paul.mueller@bluemail.ch>
	* @author Nicolas Richart <nicolas.richart@epfl.ch>
	* @author Damien Spielmann <damien.spielmann@epfl.ch>
	*
	* @date creation: Fri Jul 15 2011
	* @date last modification: Thu Apr 01 2021
	*
	* @brief Particular implementation of the structural elements in the
	* StructuralMechanicsModel
	*
	*
	* @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 "aka_named_argument.hh"
	#include "boundary_condition.hh"
	#include "model.hh"
	/* -------------------------------------------------------------------------- */

	#ifndef AKANTU_STRUCTURAL_MECHANICS_MODEL_HH_
	#define AKANTU_STRUCTURAL_MECHANICS_MODEL_HH_

	/* -------------------------------------------------------------------------- */
	namespace akantu {
	class Material;
	class MaterialSelector;
	class DumperIOHelper;
	class NonLocalManager;
	template <ElementKind kind, class IntegrationOrderFunctor>
	class IntegratorGauss;
	template <ElementKind kind> class ShapeStructural;
	} // namespace akantu

	namespace akantu {

	struct StructuralMaterial {
	Real E{0};
	Real A{1};
	Real I{0};
	Real Iz{0};
	Real Iy{0};
	Real GJ{0};
	Real rho{0};
	Real t{0};
	Real nu{0};
	};

	class StructuralMechanicsModel : public Model {
	/* ------------------------------------------------------------------------ */
	/* Constructors/Destructors */
	/* ------------------------------------------------------------------------ */
	public:
	using MyFEEngineType =
	FEEngineTemplate<IntegratorGauss, ShapeStructural, _ek_structural>;

	StructuralMechanicsModel(Mesh & mesh, UInt dim = _all_dimensions,
	const ID & id = "structural_mechanics_model");

	~StructuralMechanicsModel() override;

	/// Init full model
	void initFullImpl(const ModelOptions & options) override;

	/// Init boundary FEEngine
	void initFEEngineBoundary() override;

	/* ------------------------------------------------------------------------ */
	/* Virtual methods from SolverCallback */
	/* ------------------------------------------------------------------------ */
	/// get the type of matrix needed
	MatrixType getMatrixType(const ID & matrix_id) const override;

	/// callback to assemble a Matrix
	void assembleMatrix(const ID & matrix_id) override;

	/// callback to assemble a lumped Matrix
	void assembleLumpedMatrix(const ID & matrix_id) override;

	/// callback to assemble the residual (rhs)
	void assembleResidual() override;

	void assembleResidual(const ID & residual_part) override;

	bool canSplitResidual() const override { return true; }

	void afterSolveStep(bool converged) override;

	/// compute kinetic energy
	Real getKineticEnergy();

	/// compute potential energy
	Real getPotentialEnergy();

	/// compute the specified energy
	Real getEnergy(const ID & energy);

	/**
	* \brief This function computes the an approximation of the lumped mass.
	*
	* The mass is computed by looping over all beams and computing their mass.
	* The mass of a single beam is computed by the (initial) length of the beam,
	* its cross sectional area and its density.
	* The beam mass is then equaly distributed among the two nodes.
	*
	* For computing the rotational inertia, the function assumes that the mass of
	* a node is uniformaly distributed inside a disc (2D) or a sphere (3D). The
	* size of that disc, depends on the volume of the beam.
	*
	* Note that the computation of the mass is not unambigius.
	* The reason for this is, that the units of `StructralMaterial::rho` are not
	* clear. By default the function assumes that its unit are 'Mass per Volume'.
	* However, this makes the computed mass different than the consistent mass,
	* which seams to assume that its units are 'mass per unit length'.
	* The main difference between thge two are not the values, but that the
	* first version depends on `StructuralMaterial::A` while the later does not.
	* By defining the macro `AKANTU_STRUCTURAL_MECHANICS_CONSISTENT_LUMPED_MASS`
	* the function will compute the mass in a way that is consistent with the
	* consistent mass matrix.
	*
	* \note The lumped mass is not stored inside the DOFManager.
	*
	* \param ghost_type Should ghost types be computed.
	*/
	void assembleLumpedMassMatrix();

	/* ------------------------------------------------------------------------ */
	/* Virtual methods from Model */
	/* ------------------------------------------------------------------------ */
	protected:
	/// get some default values for derived classes
	std::tuple<ID, TimeStepSolverType>
	getDefaultSolverID(const AnalysisMethod & method) override;

	ModelSolverOptions
	getDefaultSolverOptions(const TimeStepSolverType & type) const override;

	static UInt getNbDegreeOfFreedom(ElementType type);

	/* ------------------------------------------------------------------------ */
	/* Methods */
	/* ------------------------------------------------------------------------ */
	void initSolver(TimeStepSolverType time_step_solver_type,
	NonLinearSolverType non_linear_solver_type) override;

	/// initialize the model
	void initModel() override;

	/// compute the stresses per elements
	void computeStresses();

	/// compute the nodal forces
	void assembleInternalForce();

	/// compute the nodal forces for an element type
	void assembleInternalForce(ElementType type, GhostType gt);

	/// assemble the stiffness matrix
	void assembleStiffnessMatrix();

	/// assemble the mass matrix for consistent mass resolutions
	void assembleMassMatrix();

	protected:
	/// assemble the mass matrix for either _ghost or _not_ghost elements
	void assembleMassMatrix(GhostType ghost_type);

	/// computes rho
	void computeRho(Array<Real> & rho, ElementType type, GhostType ghost_type);

	/// finish the computation of residual to solve in increment
	void updateResidualInternal();

	/* ------------------------------------------------------------------------ */
	private:
	template <ElementType type> void assembleStiffnessMatrix();
	template <ElementType type> void computeStressOnQuad();
	template <ElementType type>
	void computeTangentModuli(Array<Real> & tangent_moduli);

	/* ------------------------------------------------------------------------ */
	/* Dumpable interface */
	/* ------------------------------------------------------------------------ */
	public:
	std::shared_ptr<dumpers::Field>
	createNodalFieldReal(const std::string & field_name,
	const std::string & group_name,
	bool padding_flag) override;

	std::shared_ptr<dumpers::Field>
	createNodalFieldBool(const std::string & field_name,
	const std::string & group_name,
	bool padding_flag) override;

	std::shared_ptr<dumpers::Field>
	createElementalField(const std::string & field_name,
	const std::string & group_name, bool padding_flag,
	UInt spatial_dimension, ElementKind kind) override;

	/* ------------------------------------------------------------------------ */
	/* Accessors */
	/* ------------------------------------------------------------------------ */
	public:
	/// set the value of the time step
	void setTimeStep(Real time_step, const ID & solver_id = "") override;

	/// get the StructuralMechanicsModel::displacement vector
	AKANTU_GET_MACRO(Displacement, *displacement_rotation, Array<Real> &);

	/// get the StructuralMechanicsModel::velocity vector
	AKANTU_GET_MACRO(Velocity, *velocity, Array<Real> &);

	/// get the StructuralMechanicsModel::acceleration vector, updated
	/// by
	/// StructuralMechanicsModel::updateAcceleration
	AKANTU_GET_MACRO(Acceleration, *acceleration, Array<Real> &);

	/// get the StructuralMechanicsModel::external_force vector
	AKANTU_GET_MACRO(ExternalForce, *external_force, Array<Real> &);

	/// get the StructuralMechanicsModel::internal_force vector (boundary forces)
	AKANTU_GET_MACRO(InternalForce, *internal_force, Array<Real> &);

	/// get the StructuralMechanicsModel::boundary vector
	AKANTU_GET_MACRO(BlockedDOFs, *blocked_dofs, Array<bool> &);

	/**
	* Returns a const reference to the array that stores the lumped mass.
	*
	* The returned array has dimension `N x d` where `N` is the number of nodes
	* and `d`, is the number of degrees of freedom per node.
	*/
	inline const Array<Real> & getLumpedMass() const {
	if (this->mass == nullptr) {
	AKANTU_EXCEPTION("The pointer to the mass was not allocated.");
	};
	return *(this->mass);
	};

	// These function is an alias, for compability with the solid mechanics
	inline const Array<Real> & getMass() const { return this->getLumpedMass(); }

	// Creates the array for storing the mass
	bool allocateLumpedMassArray();

	/**
	* Tests if *this has a lumped mass pointer.
	*/
	inline bool hasLumpedMass() const { return (this->mass != nullptr); };

	AKANTU_GET_MACRO_BY_ELEMENT_TYPE_CONST(RotationMatrix, rotation_matrix, Real);

	AKANTU_GET_MACRO_BY_ELEMENT_TYPE_CONST(Stress, stress, Real);

	AKANTU_GET_MACRO_BY_ELEMENT_TYPE(ElementMaterial, element_material, UInt);

	AKANTU_GET_MACRO_BY_ELEMENT_TYPE(Set_ID, set_ID, UInt);

	/**
	* \brief This function adds the `StructuralMaterial` material to the list of
	* materials managed by *this.
	*
	* It is important that this function might invalidate all references to
	* structural materials, that were previously optained by `getMaterial()`.
	*
	* \param material The new material.
	*
	* \return The ID of the material that was added.
	*
	* \note The return type is is new.
	*/
	UInt addMaterial(StructuralMaterial & material, const ID & name = "");

	const StructuralMaterial &
	getMaterialByElement(const Element & element) const;

	/**
	* \brief Returns the ith material of *this.
	* \param i The ith material
	*/
	const StructuralMaterial & getMaterial(UInt material_index) const;

	const StructuralMaterial & getMaterial(const ID & name) const;

	/**
	* \brief Returns the number of the different materials inside *this.
	*/
	UInt getNbMaterials() const { return materials.size(); }

	/* ------------------------------------------------------------------------ */
	/* Boundaries (structural_mechanics_model_boundary.cc) */
	/* ------------------------------------------------------------------------ */
	public:
	/// Compute Linear load function set in global axis
	void computeForcesByGlobalTractionArray(const Array<Real> & traction_global,
	ElementType type);

	/// Compute Linear load function set in local axis
	void computeForcesByLocalTractionArray(const Array<Real> & tractions,
	ElementType type);

	/* ------------------------------------------------------------------------ */
	/* Class Members */
	/* ------------------------------------------------------------------------ */
	private:
	/// time step
	Real time_step;

	/// conversion coefficient form force/mass to acceleration
	Real f_m2a;

	/// displacements array
	std::unique_ptr<Array<Real>> displacement_rotation;

	/// velocities array
	std::unique_ptr<Array<Real>> velocity;

	/// accelerations array
	std::unique_ptr<Array<Real>> acceleration;

	/// forces array
	std::unique_ptr<Array<Real>> internal_force;

	/// forces array
	std::unique_ptr<Array<Real>> external_force;

	/**
	* \brief This is the "lumped" mass array.
	*
	* It is a bit special, since it is not a one dimensional array, bit it is
	* actually a matrix. The number of rows equals the number of nodes. The
	* number of colums equals the number of degrees of freedoms per node. This
	* layout makes the thing a bit more simple.
	*
	* Note that it is only allocated in case, the "Lumped" mode is enabled.
	*/
	std::unique_ptr<Array<Real>> mass;

	/// boundaries array
	std::unique_ptr<Array<bool>> blocked_dofs;

	/// stress array
	ElementTypeMapArray<Real> stress;

	ElementTypeMapArray<UInt> element_material;

	// Define sets of beams
	ElementTypeMapArray<UInt> set_ID;

	/// number of degre of freedom
	UInt nb_degree_of_freedom;

	// Rotation matrix
	ElementTypeMapArray<Real> rotation_matrix;

	// /// analysis method check the list in akantu::AnalysisMethod
	// AnalysisMethod method;

	/// flag defining if the increment must be computed or not
	bool increment_flag;

	bool need_to_reassemble_mass{true};
	bool need_to_reassemble_stiffness{true};
	bool need_to_reassemble_lumpedMass{true};

	/* ------------------------------------------------------------------------ */
	std::vector<StructuralMaterial> materials;
	std::map<std::string, UInt> materials_names_to_id;
	};

	} // namespace akantu

	#include "structural_mechanics_model_inline_impl.hh"

	#endif /* AKANTU_STRUCTURAL_MECHANICS_MODEL_HH_ */

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