Description

Load for adding mass and inertia to a body.

Note that a ChBody already has a mass an inertia tensor, however for speed optimization reasons the ChBody mass is limited to zero offset of center of mass, moreover it does not generate a gyroscopical damping matrix. Therefore, you can use this load if you need:

an offset between the body and its center of mass
a gyroscopic damping matrix (and inertial stiffness matrix), ex. it may affect for advanced aeroelastic modal analysis. Note that you must use the solvers for finite elements in order to exploit this feature.

#include <ChLoadsBody.h>

Inheritance diagram for chrono::ChLoadBodyInertia:

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Collaboration diagram for chrono::ChLoadBodyInertia:

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Public Member Functions
	ChLoadBodyInertia (std::shared_ptr< ChBody > body, const ChVector3d &offset, const double m, const ChVector3d &IXX=VNULL, const ChVector3d &IXY=VNULL)

virtual ChLoadBodyInertia *	Clone () const override
	"Virtual" copy constructor (covariant return type).

void	SetInertia (const ChMatrix33<> &newXInertia)
	Set the inertia tensor of the body, assumed in the body reference basis, with body reference as center. More...

const ChMatrix33 &	GetInertia () const
	Set the inertia tensor of the body, assumed in the body reference basis, with body reference as center. More...

void	SetInertiaXX (const ChVector3d &iner)
	Set the diagonal part of the inertia tensor (Ixx, Iyy, Izz values). More...

ChVector3d	GetInertiaXX () const
	Get the diagonal part of the inertia tensor (Ixx, Iyy, Izz values). More...

void	SetInertiaXY (const ChVector3d &iner)
	Set the off-diagonal part of the inertia tensor (Ixy, Ixz, Iyz values). More...

ChVector3d	GetInertiaXY () const
	Get the extra-diagonal part of the inertia tensor (Ixy, Ixz, Iyz values). More...

virtual void	ComputeQ (ChState state_x, ChStateDelta state_w) override
	Compute the generalized load(s). More...

virtual void	ComputeJacobian (ChState state_x, ChStateDelta state_w) override
	Compute the K=-dQ/dx, R=-dQ/dv, M=-dQ/da Jacobians. More...

virtual void	LoadIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
	Just for efficiency, override the default LoadIntLoadResidual_Mv, because we can do this in a simplified way. More...

Public Member Functions inherited from chrono::ChLoadCustom
	ChLoadCustom (std::shared_ptr< ChLoadable > loadable_object)

virtual int	LoadGetNumCoordsPosLevel () override
	Gets the number of DOFs affected by this load (position part).

virtual int	LoadGetNumCoordsVelLevel () override
	Gets the number of DOFs affected by this load (speed part).

virtual void	LoadGetStateBlock_x (ChState &mD) override
	Gets all the current DOFs packed in a single vector (position part).

virtual void	LoadGetStateBlock_w (ChStateDelta &mD) override
	Gets all the current DOFs packed in a single vector (speed part).

virtual void	LoadStateIncrement (const ChState &x, const ChStateDelta &dw, ChState &x_new) override
	Increment a packed state (e.g., as obtained by LoadGetStateBlock_x()) by a given packed state-delta. More...

virtual int	LoadGetNumFieldCoords () override
	Number of coordinates in the interpolated field. More...

virtual void	LoadIntLoadResidual_F (ChVectorDynamic<> &R, double c) override
	Add the internal loads Q (pasted at global offsets) into a global vector R, multiplied by a scaling factor c. More...

virtual void	LoadIntLoadLumpedMass_Md (ChVectorDynamic<> &Md, double &err, const double c) override
	Add the lumped mass to an Md vector, representing a mass diagonal matrix. More...

virtual void	CreateJacobianMatrices () override
	Create the Jacobian loads if needed and set the ChVariables referenced by the sparse KRM block.

virtual ChVectorDynamic &	GetQ ()
	Access the generalized load vector Q.

Public Member Functions inherited from chrono::ChLoadBase
ChLoadJacobians *	GetJacobians ()
	Access the Jacobians (if any, i.e. if this is a stiff load).

virtual void	Update (double time)
	Update, called at least at each time step. More...

virtual void	InjectKRMMatrices (ChSystemDescriptor &descriptor)
	Register with the given system descriptor any ChKRMBlock objects associated with this item.

virtual void	LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor)
	Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...

Public Member Functions inherited from chrono::ChObj
	ChObj (const ChObj &other)

int	GetIdentifier () const
	Get the unique integer identifier of this object. More...

void	SetTag (int tag)
	Set an object integer tag (default: -1). More...

int	GetTag () const
	Get the tag of this object.

void	SetName (const std::string &myname)
	Set the name of this object.

const std::string &	GetName () const
	Get the name of this object.

double	GetChTime () const
	Gets the simulation time of this object.

void	SetChTime (double m_time)
	Sets the simulation time of this object.

virtual void	ArchiveOut (ChArchiveOut &archive_out)
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIn (ChArchiveIn &archive_in)
	Method to allow de-serialization of transient data from archives.

virtual std::string &	ArchiveContainerName ()

Additional Inherited Members
Public Attributes inherited from chrono::ChLoadCustom
std::shared_ptr< ChLoadable >	loadable

ChVectorDynamic	load_Q

Protected Member Functions inherited from chrono::ChObj
int	GenerateUniqueIdentifier ()

Protected Attributes inherited from chrono::ChLoadBase
ChLoadJacobians *	m_jacobians

Protected Attributes inherited from chrono::ChObj
double	ChTime
	object simulation time

std::string	m_name
	object name

int	m_identifier
	object unique identifier

int	m_tag
	user-supplied tag

Constructor & Destructor Documentation

◆ ChLoadBodyInertia()

chrono::ChLoadBodyInertia::ChLoadBodyInertia	(	std::shared_ptr< ChBody >	body,
		const ChVector3d &	offset,
		const double	m,
		const ChVector3d &	IXX = `VNULL`,
		const ChVector3d &	IXY = `VNULL`
	)

Parameters

body	object to apply additional inertia to
offset	offset of the center of mass, in body coordinate system
m	added mass [kg]
IXX	added moments of inertia (in body frame, centered in body)
IXY	added products of inertia values (in body frame, centered in body)

Member Function Documentation

◆ ComputeJacobian()

void chrono::ChLoadBodyInertia::ComputeJacobian	(	ChState *	state_x,
		ChStateDelta *	state_w
	)

overridevirtual

Compute the K=-dQ/dx, R=-dQ/dv, M=-dQ/da Jacobians.

Implementation in a derived class should load the Jacobian matrices K, R, M in the structure 'm_jacobians'. Note the sign that is flipped because we assume equations are written with Q moved to left-hand side. This override uses analytic expressions (for example, R is the gyroscopic damping matrix).

Parameters

state_x	state position to evaluate Jacobians
state_w	state speed to evaluate Jacobians

Reimplemented from chrono::ChLoadCustom.

◆ ComputeQ()

void chrono::ChLoadBodyInertia::ComputeQ	(	ChState *	state_x,
		ChStateDelta *	state_w
	)

overridevirtual

Compute the generalized load(s).

In this case, computes the quadratic (centrifugal, gyroscopic) terms. Signs are negative as Q assumed at right hand side, so Q= -Fgyro -Fcentrifugal The M*a term is not added: to this end one could use LoadIntLoadResidual_Mv afterward.

Parameters

state_x	state position to evaluate Q
state_w	state speed to evaluate Q

Implements chrono::ChLoadBase.

◆ GetInertia()

const ChMatrix33& chrono::ChLoadBodyInertia::GetInertia ( ) const

inline

Set the inertia tensor of the body, assumed in the body reference basis, with body reference as center.

The return 3x3 symmetric matrix contains the following values:

 [ int{y^2+z^2}dm    -int{xy}dm    -int{xz}dm    ]
 [                  int{x^2+z^2}   -int{yz}dm    ]
 [       (symm.)                  int{x^2+y^2}dm ]

◆ GetInertiaXX()

ChVector3d chrono::ChLoadBodyInertia::GetInertiaXX ( ) const

Get the diagonal part of the inertia tensor (Ixx, Iyy, Izz values).

The vector contains these values, assumed in the body reference basis, with body reference as center:

  [ int{y^2+z^2}dm   int{x^2+z^2}   int{x^2+y^2}dm ]

◆ GetInertiaXY()

ChVector3d chrono::ChLoadBodyInertia::GetInertiaXY ( ) const

Get the extra-diagonal part of the inertia tensor (Ixy, Ixz, Iyz values).

The vector contains these values, assumed in the body reference basis, with body reference as center:

  [ -int{xy}dm   -int{xz}dm   -int{yz}dm ]

◆ LoadIntLoadResidual_Mv()

void chrono::ChLoadBodyInertia::LoadIntLoadResidual_Mv	(	ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	w,
		const double	c
	)

overridevirtual

Just for efficiency, override the default LoadIntLoadResidual_Mv, because we can do this in a simplified way.

Parameters

R	result: the R residual, R += cMw
w	the w vector
c	scaling factor

Reimplemented from chrono::ChLoadCustom.

◆ SetInertia()

void chrono::ChLoadBodyInertia::SetInertia ( const ChMatrix33<> & newXInertia )

Set the inertia tensor of the body, assumed in the body reference basis, with body reference as center.

The provided 3x3 matrix should be symmetric and contain the inertia tensor as: system:

              [ int{y^2+z^2}dm    -int{xy}dm    -int{xz}dm    ]
newXInertia = [                  int{x^2+z^2}   -int{yz}dm    ]
              [     (symm.)                    int{x^2+y^2}dm ]

◆ SetInertiaXX()

void chrono::ChLoadBodyInertia::SetInertiaXX ( const ChVector3d & iner )

Set the diagonal part of the inertia tensor (Ixx, Iyy, Izz values).

The vector should contain these moments of inertia, assumed in the body reference basis, with body reference as center:

  iner = [  int{y^2+z^2}dm   int{x^2+z^2}   int{x^2+y^2}dm ]

◆ SetInertiaXY()

void chrono::ChLoadBodyInertia::SetInertiaXY ( const ChVector3d & iner )

Set the off-diagonal part of the inertia tensor (Ixy, Ixz, Iyz values).

The vector contains these values, assumed in the body reference basis, with body reference as center:

  iner = [ -int{xy}dm   -int{xz}dm   -int{yz}dm ]

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

/builds/uwsbel/chrono/src/chrono/physics/ChLoadsBody.h
/builds/uwsbel/chrono/src/chrono/physics/ChLoadsBody.cpp

Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ ChLoadBodyInertia()

Member Function Documentation

◆ ComputeJacobian()

◆ ComputeQ()

◆ GetInertia()

◆ GetInertiaXX()

◆ GetInertiaXY()

◆ LoadIntLoadResidual_Mv()

◆ SetInertia()

◆ SetInertiaXX()

◆ SetInertiaXY()