Class containing a cable element object, allowing for disks and spheres to be connected. More...

#include <NetCableElement.h>

Inheritance diagram for NetCableElement:

Collaboration diagram for NetCableElement:

Public Member Functions
	NetCableElement (const NetCableElement *old)

	NetCableElement (const NetCableElementSpec *spec)

void	AddEndForces (double deltaT, const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater, double adForceA[3], double adForceB[3], bool isScreen=false)

void	SetConstants ()
	Calculates parameters and sets physical constants.

void	CalcMassAndWeight ()
	Calculates the mass and weight of the element in water.

bool	Divide (int aiNodes[2], int newNode, int newElementID, NetCableElement **sNewCable)
	Divides the element in two.

bool	CheckAndInitialize ()
	Does the initialization and checking to make sure that the element is ready for simulation.

void	DeleteSpheresAndDisks ()

void	AddSpheres (double adD, double adMass, double *adPos, std::vector< std::string > VsSphereMaterial, unsigned int num)

void	AddDisks (double adD, double adThickness, double adMass, double adPos, std::vector< std::string > VsDiskMaterial, unsigned int num)

double	GetStrainEnergy (double deltaT, const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater)

void	StrainEnergyGradient (const double adPosA[3], const double adPosB[3], double gradA[3], double gradB[3]) const

double	GetEffectiveStiffness () const

double	GetMeanTensionForce () const
	The mean-tension part of the axial force, (1 − eFactor) · mean tension [N]; constant within a step (owner ruling R64).

double	GetEffectiveDamping () const

double	GetTangentialDragFactor () const

double	GetNormalDragFactor () const
	Normal drag prefactor (= ma_dNormalDragFactor).

double	SurfaceHalfSize () const override
	The largest of the element's and its floats' half-sizes, for the surface gate (R66).

Public Member Functions inherited from CableElDynStiff
	CableElDynStiff ()
	The constructor.

	~CableElDynStiff ()
	The destructor.

virtual void	UpdateLength (double newLength, double step, bool forceUpdate=false)
	Updates the length of the cable element, and its dependant properties.

void	UpdateMeanTension (double step)
	Updates the mean tension of the cable element.

void	UpdateMeanTensionAt (const double adPosA[3], const double adPosB[3], double step)

double	GetEFactor () const
	Returns the current stiffness reduction factor (1 = full stiffness, <1 = reduced for numerical stability).

virtual void	AddStructuralForces (double adForceA[3], double adForceB[3])
	Adds the forces from tension and internal damping to the nodes. CalcFoundation must be run first.

Public Member Functions inherited from CableElBasics
	CableElBasics ()
	The constructor.

	~CableElBasics ()
	The destructor.

virtual void	AddEndForces (const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater, double adForceA[3], double adForceB[3])
	Calculates the end forces on the cable element.

double	GetDampingCoeff () const
	Returns the structural damping coefficient (negative value: -2dampRatioareasqrt(Erho)).

virtual void	UpdateLength (double newLength)
	Upates the length of the cable element, and its dependant properties.

double	GetLength ()

void	SetSurfaceElevation (double etaA, double etaB)

void	SetWaveAcceleration (const double acceleration[3])

double	InertiaShare () const
	The inertia force factor of one end node: half of (1 + Ca) rho V f (environment::cylinder_hydro::InertiaForceFactor).

void	WaveExcitationPositionJacobian (const double posA[3], const double posB[3], const double acceleration[3], double dF_dpB[9]) const

Public Attributes
double	m_nodeOffset
	The offset between the original nodes of the added node of this cable.

int	m_fromNodes [2]
	The nodes which this cable is constructed by dividing.

int	m_conn [2]
	The node numbers that the element is connected to.

double	m_refineFactor
	The factor telling how much mesh refinement is desired for this element.

unsigned int	m_numSpheres
	The number of spheres connected.

double *	m_sphereD
	The diameter of the connected spheres.

double *	m_sphereMass
	The mass of the connected spheres.

double *	m_spherePos
	The position of the connected spheres.

unsigned int	m_numDisks
	The number of disks connected.

double *	m_diskD
	The diameter of the connected disks.

double *	m_diskThickness
	The thickness of the connected disks.

double *	m_diskMass
	The mass of the connected disks.

double *	m_diskPos
	The position of the connected disks.

double	m_addedWeightInWater
	The weight in water added to the element.

std::vector< std::string >	m_VsDiskMeshName
	The names of the materials of the attached disks.

std::vector< std::string >	m_VsSphereMeshName
	The names of the materials of the attached spheres.

Public Attributes inherited from CableElDynStiff
double	m_maxStep
	The maximum step of the integration routine.

double	m_meanTension
	The mean tension of the cable element.

double	m_eAdaptationPeriod
	The time constant of the adaptation of the mean tension.

double	m_stepSafetyFactor
	The safety factor when calculating the Young modulus of the element.

Public Attributes inherited from CableElBasics
unsigned long	m_iD
	The ID of the element.

std::string	m_cableName
	The name of the parent cable.

double	m_dL0
	The relaxed length of the element.

double	m_dD
	The diameter of the element.

double	m_dE
	The Young modulus of the element.

double	m_rho
	The density of the element material.

double	m_addedWeightInWater
	The weight in water added to the element.

double	m_tangentialFrictionCoeff
	The tangential drag coefficient of the cable element.

double	m_normalDragCoeff
	The normal drag coefficient of the cable element.

double	m_rhoWater
	The density of the surrounding fluid: the water density blended with the air density by the submerged fraction (CalcFoundation).

double	m_rhoAir = 1.2
	The air density, kg/m³; the owner sets the environment's (cable_air::EnvironmentAirDensity, owner ruling R65).

double	m_minLength
	The minimum length of the element.

double	m_maxTension
	The maximum tension in the element.

double	m_dampingRatio
	The relative damping ratio of the cable.

double	m_eA
	The linear stiffness of the element.

double	m_dA
	The cross sectional area of the cable.

double	m_weightInWater [2]
	The weight in water distributed to each node.

double	m_massInWater [2]
	The mass in water distributed to each node.

double	m_weightInWaterPerMeter [2]
	The weight in water distributed to each node, per meter cable.

double	m_massInWaterPerMeter [2]
	The mass in water distributed to each node, per meter cable.

Protected Member Functions
bool	AppendagesNearTheSurface () override
	True while a float may be at the surface (R66).

double	SphereWetFraction (unsigned int i) const
	The wet fraction of sphere i, its own cap at its position (R66).

double	DiskWetFraction (unsigned int i) const
	The wet fraction of disk i (R66).

void	AddWaveExcitation (double adForceA[3], double adForceB[3]) const
	Adds the Froude-Krylov and added-mass wave excitation of the element (normal to it, R108) and its floats (the full acceleration) (R67).

void	AddHydroForcesAppendices (double adForceA[3], double adForceB[3])
	Calculates the hydrodynamic forces on spheres and disks attached to the cable.

Protected Member Functions inherited from CableElBasics
void	AddWaveExcitationCable (double adForceA[3], double adForceB[3]) const
	Adds the rope's Froude-Krylov and added-mass wave excitation (owner rulings R67, R104). CalcFoundation must be run first.

void	CalcFoundation (const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], const double adFluidVel[3], const double rhoWater)

void	AddGravityBuoyancy (double adForceA[3], double adForceB[3], const double adPosA[3], const double adPosB[3])
	Adds the forces from gravity and buoyancy to the nodes. CalcFoundation must be run first.

void	AddHydroForcesCable (double adForceA[3], double adForceB[3])
	Calculates the hydrodynamic forces on the cable and the spheres and disks attached to it. CalcFoundation must be run first.

Protected Attributes
bool	m_appendagesWereNearTheSurface = false
	AppendagesNearTheSurface at the last call.

double	m_dragCoeffSphere
	The drag coefficient of a sphere.

double	m_normalDragCoeffDisk
	The normal drag coefficient of a disk.

Protected Attributes inherited from CableElDynStiff
double	ma_dEps
	The stretching of the cable.

double	m_eFactor
	The factor multiplied by the Young modulus.

double	m_meanTensionDamp
	The damping of the development of the mean tension.

double	ma_adMeanTensionForceA [3]

double	ma_dAdaptationDamping

sfh::filters::PID	m_MeanTensionController

Protected Attributes inherited from CableElBasics
double	m_surfaceElevation [2] = {0.0, 0.0}
	η above the ends [m] (SetSurfaceElevation).

double	m_submergence [2] = {1e10, 1e10}
	z + η at the ends at the last CalcFoundation [m]; deep before the first.

double	m_axisVertical = 0.0
	The vertical component of the unit axis A→B at the last CalcFoundation.

double	m_wetFraction = 1.0
	The element's wet fraction at the last CalcFoundation (CylinderWetFraction).

double	m_rhoWaterFull = 1025.0
	The water density the owner passed, unblended [kg/m³].

double	m_waveAcceleration [3] = {0.0, 0.0, 0.0}
	The water particle acceleration at the element (SetWaveAcceleration) [m/s²].

double	ma_adDirection [3]
	Memory allocation to increase the computational efficiency.

double	ma_dDampingCoeff
	A intermediate damping calculation to increase the computational efficiency.

double	ma_adVel [3]
	The average hydrodynamic velocity of the element.

double	ma_dVelAmp
	The scalar average hydrodynamic velocity of the element.

double	ma_adVt [3]
	The average tangential hydrodynamic velocity of the element.

double	ma_dVtAmp
	The scalar average tangential hydrodynamic velocity of the element.

double	ma_adVn [3]
	The average normal hydrodynamic velocity of the element.

double	ma_dVnAmp
	The scalar average normal hydrodynamic velocity of the element.

double	ma_adVn_A [3]
	The hydrodynamic normal velocity of the end A.

double	ma_adVn_B [3]
	The hydrodynamic normal velocity of the end B.

double	ma_dVnAmp_A
	The scalar hydrodynamic normal velocity of the end A.

double	ma_dVnAmp_B
	The scalar hydrodynamic normal velocity of the end B.

double	ma_dLength
	The actual distance between the ends.

double	ma_dCompressionSpeed
	The speed at which the distance between the two ends decreases.

double	ma_dTangentialDragFactor
	A factor used when calculating the tangential drag force.

double	ma_dNormalDragFactor
	A factor used when calculating the normal drag force.

Additional Inherited Members
Static Public Attributes inherited from CableElBasics
static constexpr double	kAddedMassCoefficient = environment::cylinder_hydro::kCylinderAddedMassCoefficient

Detailed Description

Author: Karl-Johan Reite

Member Function Documentation

◆ AppendagesNearTheSurface()

bool NetCableElement::AppendagesNearTheSurface ( )

overrideprotectedvirtual

Reimplemented from CableElBasics.

◆ CalcMassAndWeight()

void NetCableElement::CalcMassAndWeight ( )

virtual

Reimplemented from CableElBasics.

◆ CheckAndInitialize()

bool NetCableElement::CheckAndInitialize ( )

virtual

Reimplemented from CableElDynStiff.

◆ GetEffectiveDamping()

double NetCableElement::GetEffectiveDamping ( ) const

inline

Effective axial damping coefficient used in the structural force (ma_dDampingCoeff * sqrt(eFactor)); negative by construction. Exposed for analytical Jacobian computation in NetStructure.

◆ GetEffectiveStiffness()

double NetCableElement::GetEffectiveStiffness ( ) const

inline

Effective linear stiffness used in the structural force (eFactor * EA). Exposed for analytical Jacobian computation in NetStructure.

◆ GetTangentialDragFactor()

double NetCableElement::GetTangentialDragFactor ( ) const

inline

Tangential drag prefactor (= ma_dTangentialDragFactor). Reflects the rhoWater used in the most recent CalcFoundation call.

◆ SetConstants()

void NetCableElement::SetConstants ( )

virtual

Reimplemented from CableElBasics.

◆ StrainEnergyGradient()

void NetCableElement::StrainEnergyGradient	(	const double	adPosA[3],
		const double	adPosB[3],
		double	gradA[3],
		double	gradB[3]
	)		const

Derivative of GetStrainEnergy() with respect to the end positions, which are its only state dependence: L0 and the full stiffness EA are fixed. Ignores the 1 mm and 10 km length saturation of CableElBasics, where the true derivative is zero.

Parameters

[out]	gradA	Derivative with respect to end A [N].
[out]	gradB	Derivative with respect to end B [N].

◆ SurfaceHalfSize()

double NetCableElement::SurfaceHalfSize ( ) const

overridevirtual

Reimplemented from CableElBasics.

The documentation for this class was generated from the following file:

webfhsim/reloadrepos/fhsim_marine_elements/src/net/NetCableElement.h

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ AppendagesNearTheSurface()

◆ CalcMassAndWeight()

◆ CheckAndInitialize()

◆ GetEffectiveDamping()

◆ GetEffectiveStiffness()

◆ GetTangentialDragFactor()

◆ SetConstants()

◆ StrainEnergyGradient()

◆ SurfaceHalfSize()