Description

Class for all elements whose stiffness matrix can be seen as an NxN block-matrix split among N nodes.

Most FEA elements inherited from ChElementGeneric need to implement at most the two fundamental methods ComputeKRMmatricesGlobal(), ComputeInternalForces(), and optionally ComputeGravityForces().

#include <ChElementGeneric.h>

Inheritance diagram for chrono::fea::ChElementGeneric:

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Collaboration diagram for chrono::fea::ChElementGeneric:

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Public Member Functions
ChKRMBlock &	Kstiffness ()
	Access the proxy to stiffness, for sparse solver.

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

virtual void	EleIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
	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 This default implementation is VERY INEFFICIENT.

virtual void	EleIntLoadLumpedMass_Md (ChVectorDynamic<> &Md, double &error, const double c) override
	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) override
	Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c This default implementation is VERY INEFFICIENT. More...

virtual void	ComputeGravityForces (ChVectorDynamic<> &Fg, const ChVector3d &G_acc) override
	Compute the gravitational forces. More...

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

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

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

virtual void	VariablesFbLoadInternalForces (double factor=1.) override
	Add the internal forces, expressed as nodal forces, into the encapsulated ChVariables.

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

Public Member Functions inherited from chrono::fea::ChElementBase
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	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	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.

Protected Attributes
ChKRMBlock	Kmatr

Member Function Documentation

◆ ComputeGravityForces()

void chrono::fea::ChElementGeneric::ComputeGravityForces	(	ChVectorDynamic<> &	Fg,
		const ChVector3d &	G_acc
	)

overridevirtual

Compute the gravitational forces.

This default implementation (POTENTIALLY INEFFICIENT) uses a temporary ChLoaderGravity that applies the load to elements only if they are inherited by ChLoadableUVW so it can use GetDensity() and Gauss quadrature.

Implements chrono::fea::ChElementBase.

Reimplemented 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, and chrono::fea::ChElementCableANCF.

◆ ComputeMmatrixGlobal()

void chrono::fea::ChElementGeneric::ComputeMmatrixGlobal ( ChMatrixRef M )

overridevirtual

Calculate the mass matrix, expressed in global reference.

This default implementation (POTENTIALLY VERY INEFFICIENT) should be overriden by derived classes a more efficient version.

Implements chrono::fea::ChElementBase.

Reimplemented in chrono::fea::ChElementShellReissner4, chrono::fea::ChElementShellANCF_3833, chrono::fea::ChElementShellANCF_3443, chrono::fea::ChElementHexaANCF_3843, chrono::fea::ChElementShellANCF_3423, chrono::fea::ChElementBeamANCF_3333, chrono::fea::ChElementBeamANCF_3243, and chrono::fea::ChElementCableANCF.

◆ EleIntLoadLumpedMass_Md()

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

overridevirtual

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 This default implementation is VERY INEFFICIENT.

Reimplemented from chrono::fea::ChElementBase.

Reimplemented in chrono::fea::ChElementShellBST.

◆ EleIntLoadResidual_F_gravity()

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

overridevirtual

Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c This default implementation is VERY INEFFICIENT.

This fallback implementation uses a temp ChLoaderGravity that applies the load to elements only if they are inherited by ChLoadableUVW so it can use GetDensity() and Gauss quadrature.

Implements chrono::fea::ChElementBase.

◆ LoadKRMMatrices()

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

overridevirtual

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.

Implements chrono::fea::ChElementBase.

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

/builds/uwsbel/chrono/src/chrono/fea/ChElementGeneric.h
/builds/uwsbel/chrono/src/chrono/fea/ChElementGeneric.cpp

Description

Public Member Functions

Protected Attributes

Member Function Documentation

◆ ComputeGravityForces()

◆ ComputeMmatrixGlobal()

◆ EleIntLoadLumpedMass_Md()

◆ EleIntLoadResidual_F_gravity()

◆ LoadKRMMatrices()