Description

Base class for all finite elements, that can be used in the ChMesh physics item.

#include <ChElementBase.h>

Inheritance diagram for chrono::fea::ChElementBase:

[legend]

Public Member Functions
virtual unsigned int	GetNumNodes ()=0
	Get the number of nodes used by this element.

virtual unsigned int	GetNumCoordsPosLevel ()=0
	Get the number of coordinates in the field used by the referenced nodes. More...

virtual unsigned int	GetNumCoordsPosLevelActive ()
	Get the actual number of active degrees of freedom. More...

virtual unsigned int	GetNodeNumCoordsPosLevel (unsigned int n)=0
	Get the number of coordinates from the specified node that are used by this element. More...

virtual unsigned int	GetNodeNumCoordsPosLevelActive (unsigned int n)
	Get the actual number of active coordinates from the specified node that are used by this element. More...

virtual std::shared_ptr< ChNodeFEAbase >	GetNode (unsigned int n)=0
	Access the nth node.

virtual void	GetStateBlock (ChVectorDynamic<> &mD)=0
	Fill the D vector with the current field values at the nodes of the element, with proper ordering. More...

virtual void	ComputeMmatrixGlobal (ChMatrixRef M)=0
	Calculate the mass matrix, expressed in global reference.

virtual void	ComputeNodalMass ()
	Compute element's nodal masses.

virtual void	ComputeKRMmatricesGlobal (ChMatrixRef H, double Kfactor, double Rfactor=0, double Mfactor=0)=0
	Set H as the stiffness matrix K, scaled by Kfactor. More...

virtual void	ComputeInternalForces (ChVectorDynamic<> &Fi)=0
	Compute the internal forces. More...

virtual void	ComputeGravityForces (ChVectorDynamic<> &Fi, const ChVector3d &G_acc)=0
	Compute the gravitational forces. More...

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

virtual void	EleDoIntegration ()
	This is optionally implemented if there is some internal state that requires integration.

virtual void	EleIntLoadResidual_F (ChVectorDynamic<> &R, const double c)
	Add the internal forces (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += forces * c.

virtual void	EleIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c)
	Add the product of element mass M by a vector w (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += M * w * c.

virtual void	EleIntLoadLumpedMass_Md (ChVectorDynamic<> &Md, double &error, const double c)
	Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More...

virtual void	EleIntLoadResidual_F_gravity (ChVectorDynamic<> &R, const ChVector3d &G_acc, const double c)=0
	Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c Note that it is up to the element implementation to build a proper g vector that contains G_acc values in the proper stride (ex. More...

virtual void	InjectKRMMatrices (ChSystemDescriptor &descriptor)=0
	Register with the given system descriptor any ChKRMBlock objects associated with this item.

virtual void	LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor)=0
	Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...

virtual void	VariablesFbLoadInternalForces (double factor=1.0)
	Add the internal forces, expressed as nodal forces, into the encapsulated ChVariables. More...

virtual void	VariablesFbIncrementMq ()
	Add M*q (internal masses multiplied current 'qb'). More...

Friends
class	ChMesh

Member Function Documentation

◆ ComputeGravityForces()

virtual void chrono::fea::ChElementBase::ComputeGravityForces	(	ChVectorDynamic<> &	Fi,
		const ChVector3d &	G_acc
	)

pure virtual

Compute the gravitational forces.

Set values in the provided Fi vector (of size equal to the number of dof of element).

Implemented in chrono::fea::ChElementShellANCF_3833, chrono::fea::ChElementShellANCF_3443, chrono::fea::ChElementHexaANCF_3843, chrono::fea::ChElementBeamTaperedTimoshenko, chrono::fea::ChElementShellANCF_3423, chrono::fea::ChElementBeamANCF_3333, chrono::fea::ChElementBeamANCF_3243, chrono::fea::ChElementBeamEuler, chrono::fea::ChElementBeamIGA, chrono::fea::ChElementCableANCF, and chrono::fea::ChElementGeneric.

◆ ComputeInternalForces()

virtual void chrono::fea::ChElementBase::ComputeInternalForces ( ChVectorDynamic<> & Fi )

pure virtual

Compute the internal forces.

Set values in the provided Fi vector (of size equal to the number of dof of element).

◆ ComputeKRMmatricesGlobal()

virtual void chrono::fea::ChElementBase::ComputeKRMmatricesGlobal	(	ChMatrixRef	H,
		double	Kfactor,
		double	Rfactor = `0`,
		double	Mfactor = `0`
	)

pure virtual

Set H as the stiffness matrix K, scaled by Kfactor.

Optionally, also superimposes global damping matrix R, scaled by Rfactor, and mass matrix M, scaled by Mfactor. Matrices are expressed in global reference. Corotational elements can take the local Kl & Rl matrices and rotate them.

◆ EleIntLoadLumpedMass_Md()

virtual void chrono::fea::ChElementBase::EleIntLoadLumpedMass_Md	(	ChVectorDynamic<> &	Md,
		double &	error,
		const double	c
	)

inlinevirtual

Adds the lumped mass to a Md vector, representing a mass diagonal matrix.

Used by lumped explicit integrators. If mass lumping is impossible or approximate, adds scalar error to "error" parameter. Md += c*diag(M) or Md += c*HRZ(M) or other lumping heuristics

Reimplemented in chrono::fea::ChElementShellBST, and chrono::fea::ChElementGeneric.

◆ EleIntLoadResidual_F_gravity()

virtual void chrono::fea::ChElementBase::EleIntLoadResidual_F_gravity	(	ChVectorDynamic<> &	R,
		const ChVector3d &	G_acc,
		const double	c
	)

pure virtual

Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c Note that it is up to the element implementation to build a proper g vector that contains G_acc values in the proper stride (ex.

tetahedrons have 4x copies of G_acc in g). Note that elements can provide fast implementations that do not need to build any internal M matrix, and not even the g vector, for instance if using lumped masses.

Implemented in chrono::fea::ChElementGeneric.

◆ GetNodeNumCoordsPosLevel()

virtual unsigned int chrono::fea::ChElementBase::GetNodeNumCoordsPosLevel ( unsigned int n )

pure virtual

Get the number of coordinates from the specified node that are used by this element.

Note that this may be different from the value returned by GetNode(n)->GetNumCoordsVelLevel().

◆ GetNodeNumCoordsPosLevelActive()

virtual unsigned int chrono::fea::ChElementBase::GetNodeNumCoordsPosLevelActive ( unsigned int n )

inlinevirtual

Get the actual number of active coordinates from the specified node that are used by this element.

The default implementation returns the full number of coordinates for this element, but some elements may have nodes with fixed variables.

Reimplemented in chrono::fea::ChElementShellANCF_3443, chrono::fea::ChElementShellANCF_3833, chrono::fea::ChElementBeamANCF_3243, chrono::fea::ChElementHexaANCF_3843, chrono::fea::ChElementBeamANCF_3333, chrono::fea::ChElementShellANCF_3423, chrono::fea::ChElementCableANCF, chrono::fea::ChElementHexaANCF_3813_9, and chrono::fea::ChElementHexaANCF_3813.

◆ GetNumCoordsPosLevel()

virtual unsigned int chrono::fea::ChElementBase::GetNumCoordsPosLevel ( )

pure virtual

Get the number of coordinates in the field used by the referenced nodes.

This is for example the size (number of rows/columns) of the local stiffness matrix.

◆ GetNumCoordsPosLevelActive()

virtual unsigned int chrono::fea::ChElementBase::GetNumCoordsPosLevelActive ( )

inlinevirtual

Get the actual number of active degrees of freedom.

The default implementation returns the full number of coordinates for this element, but some elements may have nodes with fixed variables.

Reimplemented in chrono::fea::ChElementShellANCF_3443, chrono::fea::ChElementShellANCF_3833, chrono::fea::ChElementBeamANCF_3243, chrono::fea::ChElementHexaANCF_3843, chrono::fea::ChElementBeamANCF_3333, chrono::fea::ChElementShellANCF_3423, chrono::fea::ChElementCableANCF, chrono::fea::ChElementHexaANCF_3813_9, and chrono::fea::ChElementHexaANCF_3813.

◆ GetStateBlock()

virtual void chrono::fea::ChElementBase::GetStateBlock ( ChVectorDynamic<> & mD )

pure virtual

Fill the D vector with the current field values at the nodes of the element, with proper ordering.

If the D vector size is not this->GetNumCoordsPosLevel(), it will be resized. For corotational elements, field is assumed in local reference!

◆ LoadKRMMatrices()

virtual void chrono::fea::ChElementBase::LoadKRMMatrices	(	double	Kfactor,
		double	Rfactor,
		double	Mfactor
	)

pure virtual

Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects.

The resulting KRM blocks represent linear combinations of the K, R, and M matrices, with the specified coefficients Kfactor, Rfactor,and Mfactor, respectively.

Implemented in chrono::fea::ChElementGeneric.

◆ Update()

virtual void chrono::fea::ChElementBase::Update ( )

inlinevirtual

Update, called at least at each time step.

If the element has to keep updated some auxiliary data, such as the rotation matrices for corotational approach, this should be implemented in this function.

◆ VariablesFbIncrementMq()

virtual void chrono::fea::ChElementBase::VariablesFbIncrementMq ( )

inlinevirtual

Add M*q (internal masses multiplied current 'qb').

Update fb. For example, if qb is initialized with v_old using VariablesQbLoadSpeed, this method can be used in timestepping schemes that do: M*v_new = M*v_old + forces*dt. WILL BE DEPRECATED

Reimplemented in chrono::fea::ChElementGeneric.

◆ VariablesFbLoadInternalForces()

virtual void chrono::fea::ChElementBase::VariablesFbLoadInternalForces ( double factor = 1.0 )

inlinevirtual

Add the internal forces, expressed as nodal forces, into the encapsulated ChVariables.

Update the 'fb' part: qf+=forces*factor WILL BE DEPRECATED - see EleIntLoadResidual_F

Reimplemented in chrono::fea::ChElementGeneric.

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

/builds/uwsbel/chrono/src/chrono/fea/ChElementBase.h

Description

Public Member Functions

Friends

Member Function Documentation

◆ ComputeGravityForces()

◆ ComputeInternalForces()

◆ ComputeKRMmatricesGlobal()

◆ EleIntLoadLumpedMass_Md()

◆ EleIntLoadResidual_F_gravity()

◆ GetNodeNumCoordsPosLevel()

◆ GetNodeNumCoordsPosLevelActive()

◆ GetNumCoordsPosLevel()

◆ GetNumCoordsPosLevelActive()

◆ GetStateBlock()

◆ LoadKRMMatrices()

◆ Update()

◆ VariablesFbIncrementMq()

◆ VariablesFbLoadInternalForces()