InternalCable Class Reference

Inheritance diagram for InternalCable:

Collaboration diagram for InternalCable:

Public Member Functions
	InternalCable (ISimObjectCreator *creator, const SCableSpec &CableSpec)
	The constructor sets the pointer to the output object and the parser object.
	~InternalCable ()
	The destructor deletes dynamically allocated memory.
virtual void	FinalSetup (const double dT, const double *const adX, ISimObjectCreator *const creator)
virtual void	OdeFcn (const double *const adPosA, const double *const adVelA, const double *const adPosB, const double *const adVelB, const double *const adX, double *const adXDot, double dT) const
	Calculates the state derivatives and the end forces.
virtual bool	InBottomContact () const
void	EvaluateElementsAt (const double *adPosA, const double *adVelA, const double *adPosB, const double *adVelB, const double *adX, double dT) const
double	EndInertia (int end) const
void	ComputeStructuralJacobian (const double *posA, const double *velA, const double *posB, const double *velB, const double *X, double *J, int nStates, int stateOffset) const
void	AddEndpointJacobianContributions (const double *posA, const double *velA, const double *posB, const double *velB, int globalPosIdxA, int globalVelIdxA, int globalPosIdxB, int globalVelIdxB, double endInertiaA, double endInertiaB, const double *X, double *J, int nStates, int stateOffset) const
virtual bool	InitializeStates (const double *const adPosA, const double *const adVelA, const double *const adPosB, const double *const adVelB, double *const adX)
	Method for setting initial conditions when the input is known, which may be implemented in the individual simObjects.
void	UpdateCable (double newLength)
	Sets the unstretched length of the cable, divided equally between its elements.
void	AdvanceMeanTension (const double *adPosA, const double *adPosB, const double *adX, double T)
void	AddEndForcesAndInertia (double *const adEndForceA, double *const adEndForceB, double *const pdEndInertiaA, double *const pdEndInertiaB, const double *const adPosA, const double *const adVelA, const double *const adPosB, const double *const adVelB, const double *const adX, double dT)
	Adds the end forces and inertia to the supplied data structures.
double	GetLength ()
	Calculates the length of the cable.

Public Attributes
unsigned long	m_numElements
	The number of elements to divide the cable into.
unsigned long	m_numNodes
	The number of nodes of the cable.

Protected Member Functions
void	ResetAllNodeForces () const
void	AddAllElementForces (const double *const adPosA, const double *const adVelA, const double *const adPosB, const double *const adVelB, const double *const adX, double dT) const
void	CalcDerivatives (const double *const adX, double *const adXDot) const
virtual void	AddElementForce (int cableElement, const double adPosA[3], const double adVelA[3], const double adPosB[3], const double adVelB[3], double adForceA[3], double adForceB[3], double dT) const
double	NodeInertia (unsigned long node) const

Protected Attributes
unsigned long *	m_iStatePos
	An array of indices to the node position states.
unsigned long *	m_iStateVel
	An array of indices to the node velocity states.
SCableSpec	m_CableSpec
	The cable specification.
double	m_eA
	The stiffness of the cable.
double	m_meanTensionTime = std::numeric_limits<double>::quiet_NaN()
	The time of the last AdvanceMeanTension.
CableElDynStiff **	m_cableElements
	An array holding the cable elements.
double **	m_aadForceA
	The force on the A nodes.
double **	m_aadForceB
	The force on the B nodes.
environment::EnvironmentProvider *	m_environment
double	m_elVelWater [3]
double	m_elMeanPos [3]
double	m_elMeanVel [3]

Member Function Documentation

AddElementForce()

virtual void InternalCable::AddElementForce ( int  cableElement, const double  adPosA[3], const double  adVelA[3], const double  adPosB[3], const double  adVelB[3], double  adForceA[3], double  adForceB[3], double  dT  ) const

protectedvirtual

Reimplemented in InternalCableWithAttractor.

AddEndpointJacobianContributions()

void InternalCable::AddEndpointJacobianContributions	(	const double *	posA,
		const double *	velA,
		const double *	posB,
		const double *	velB,
		int	globalPosIdxA,
		int	globalVelIdxA,
		int	globalPosIdxB,
		int	globalVelIdxB,
		double	endInertiaA,
		double	endInertiaB,
		const double *	X,
		double *	J,
		int	nStates,
		int	stateOffset
	)		const

Adds Jacobian contributions from boundary segments when endpoints are state variables.

ComputeStructuralJacobian treats posA/posB as frozen (no J entries for them). Call this afterwards when either endpoint belongs to the state vector (junction nodes).

Parameters

posA	Position of cable endpoint A.
velA	Velocity of cable endpoint A.
posB	Position of cable endpoint B.
velB	Velocity of cable endpoint B.
globalPosIdxA	Global state index of posA; -1 if posA comes from a port.
globalVelIdxA	Global state index of velA; -1 if velA comes from a port.
globalPosIdxB	Global state index of posB; -1 if posB comes from a port.
globalVelIdxB	Global state index of velB; -1 if velB comes from a port.
endInertiaA	Inertia of junction node A (used when globalPosIdxA >= 0).
endInertiaB	Inertia of junction node B (used when globalPosIdxB >= 0).
X	Local state slice (adX + stateOffset from the SimObject's perspective).
J	Row-major Jacobian matrix (nStates x nStates), accumulated into.
nStates	Total state count for this SimObject.
stateOffset	Offset of this cable's states within the SimObject's state vector.

AdvanceMeanTension()

void InternalCable::AdvanceMeanTension	(	const double *	adPosA,
		const double *	adPosB,
		const double *	adX,
		double	T
	)

Advances the elements' dynamic-stiffness mean tension once per integrator step (owner ruling R64, MARE-0357): the owner calls this from PreOdeFcn with the step's start state, and OdeFcn and the port calculations only read it. A second call at the same or an earlier time does nothing (MARE-0330).

Parameters

adPosA	The position of end A [m].
adPosB	The position of end B [m].
adX	The states of this cable.
T	The time of the step start [s].

ComputeStructuralJacobian()

void InternalCable::ComputeStructuralJacobian	(	const double *	posA,
		const double *	velA,
		const double *	posB,
		const double *	velB,
		const double *	X,
		double *	J,
		int	nStates,
		int	stateOffset
	)		const

Computes the structural (spring+damper) contribution to the ODE Jacobian. Fills J (row-major, nStates x nStates) with contributions from all segments. Omitted terms: hydrodynamic drag, gravity/buoyancy (constants), the wave excitation (R104). stateOffset: byte offset of this cable's states within the SimObject's global state vector.

EndInertia()

double InternalCable::EndInertia

(

int

end

)

const

The inertia this cable gives end A or B (0 or 1): the end element's share of its mass, at the state the elements were last evaluated at.

EvaluateElementsAt()

void InternalCable::EvaluateElementsAt	(	const double *	adPosA,
		const double *	adVelA,
		const double *	adPosB,
		const double *	adVelB,
		const double *	adX,
		double	dT
	)		const

Evaluates the elements at a state as OdeFcn does, without the derivatives, so that the masses the Jacobian divides by are those of that state (MARE-0359). Call it before ComputeStructuralJacobian.

Parameters

adPosA	The position of end A.
adVelA	The velocity of end A.
adPosB	The position of end B.
adVelB	The velocity of end B.
adX	The states of this cable.
dT	The time [s].

InBottomContact()

virtual bool InternalCable::InBottomContact ( ) const

inlinevirtual

Whether the seafloor gave this section a force at its last OdeFcn (FISH-0086); a section without bottom contact never has one.

Reimplemented in InternalCableWithBottomContact.

NodeInertia()

double InternalCable::NodeInertia ( unsigned long  node ) const

protected

The inertia of internal node node: its share of the masses of its two elements, at the state the elements were last evaluated at (MARE-0325).

OdeFcn()

virtual void InternalCable::OdeFcn ( const double *const  adPosA, const double *const  adVelA, const double *const  adPosB, const double *const  adVelB, const double *const  adX, double *const  adXDot, double  dT  ) const

virtual

Reimplemented in InternalCableWithAttractor, and InternalCableWithBottomContact.

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

• webfhsim/reloadrepos/fhsim_marine_elements/src/cable/subroutines/InternalCable.h