Description

Hexahedronal solid element with 8 nodes (with EAS).

While technically not an ANCF element, the name is justified because the implementation can use the same ANCF machinery.

#include <ChElementHexaANCF_3813.h>

Inheritance diagram for chrono::fea::ChElementHexaANCF_3813:

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Collaboration diagram for chrono::fea::ChElementHexaANCF_3813:

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Public Types
using	ShapeVector = ChMatrixNM< double, 1, 8 >

Public Member Functions
virtual unsigned int	GetNumNodes () override
	Get number of nodes of this element.

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

virtual unsigned int	GetNumCoordsPosLevelActive () override
	Get the number of active coordinates in the field used by the referenced nodes.

virtual unsigned int	GetNodeNumCoordsPosLevel (unsigned int n) override
	Get the number of coordinates from the n-th node used by this element.

virtual unsigned int	GetNodeNumCoordsPosLevelActive (unsigned int n) override
	Get the number of active coordinates from the n-th node used by this element.

virtual std::shared_ptr< ChNodeFEAbase >	GetNode (unsigned int n) override
	Access the n-th node of this element.

virtual std::shared_ptr< ChNodeFEAxyz >	GetHexahedronNode (unsigned int n) override
	Return the specified hexahedron node (0 <= n <= 7).

void	SetNodes (std::shared_ptr< ChNodeFEAxyz > nodeA, std::shared_ptr< ChNodeFEAxyz > nodeB, std::shared_ptr< ChNodeFEAxyz > nodeC, std::shared_ptr< ChNodeFEAxyz > nodeD, std::shared_ptr< ChNodeFEAxyz > nodeE, std::shared_ptr< ChNodeFEAxyz > nodeF, std::shared_ptr< ChNodeFEAxyz > nodeG, std::shared_ptr< ChNodeFEAxyz > nodeH)
	Specify the nodes of this element.

void	SetElemNum (int kb)
	Set the element number.

void	SetStockAlpha (double a1, double a2, double a3, double a4, double a5, double a6, double a7, double a8, double a9)
	Set EAS internal parameters (stored values).

void	SetInertFlexVec (const ChVector3d &a)
	Set some element parameters (dimensions).

int	GetElemNum () const

const ChMatrixNM< double, 8, 3 > &	GetInitialPos () const
	Get initial position of the element in matrix form.

std::shared_ptr< ChNodeFEAxyz >	GetNodeA () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeB () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeC () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeD () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeE () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeF () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeG () const

std::shared_ptr< ChNodeFEAxyz >	GetNodeH () const

double	GetLengthX () const

double	GetLengthY () const

double	GetLengthZ () const

void	SetMaterial (std::shared_ptr< ChContinuumElastic > my_material)

std::shared_ptr< ChContinuumElastic >	GetMaterial () const

void	SetMooneyRivlin (bool val)
	Set whether material is Mooney-Rivlin (Otherwise linear elastic isotropic)

void	SetMRCoefficients (double C1, double C2)
	Set Mooney-Rivlin coefficients.

void	ShapeFunctions (ShapeVector &N, double x, double y, double z)
	Fills the N shape function matrix as N = [s1eye(3) s2eye(3) s3eye(3) s4eye(3)...]; ,.

void	ShapeFunctionsDerivativeX (ShapeVector &Nx, double x, double y, double z)

void	ShapeFunctionsDerivativeY (ShapeVector &Ny, double x, double y, double z)

void	ShapeFunctionsDerivativeZ (ShapeVector &Nz, double x, double y, double z)

virtual unsigned int	GetLoadableNumCoordsPosLevel () override
	Gets the number of DOFs affected by this element (position part)

virtual unsigned int	GetLoadableNumCoordsVelLevel () override
	Gets the number of DOFs affected by this element (speed part)

virtual void	LoadableGetStateBlockPosLevel (int block_offset, ChState &mD) override
	Gets all the DOFs packed in a single vector (position part)

virtual void	LoadableGetStateBlockVelLevel (int block_offset, ChStateDelta &mD) override
	Gets all the DOFs packed in a single vector (speed part)

virtual void	LoadableStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override
	Increment all DOFs using a delta.

virtual unsigned int	GetNumFieldCoords () override
	Number of coordinates in the interpolated field: here the {x,y,z} displacement.

virtual unsigned int	GetNumSubBlocks () override
	Get the number of DOFs sub-blocks.

virtual unsigned int	GetSubBlockOffset (unsigned int nblock) override
	Get the offset of the specified sub-block of DOFs in global vector.

virtual unsigned int	GetSubBlockSize (unsigned int nblock) override
	Get the size of the specified sub-block of DOFs in global vector.

virtual bool	IsSubBlockActive (unsigned int nblock) const override
	Check if the specified sub-block of DOFs is active.

virtual void	LoadableGetVariables (std::vector< ChVariables * > &mvars) override
	Get the pointers to the contained ChVariables, appending to the mvars vector.

virtual void	ComputeNF (const double U, const double V, const double W, ChVectorDynamic<> &Qi, double &detJ, const ChVectorDynamic<> &F, ChVectorDynamic<> state_x, ChVectorDynamic<> state_w) override
	Evaluate N'F , where N is some type of shape function evaluated at U,V,W coordinates of the volume, each ranging in -1..+1 F is a load, N'F is the resulting generalized load Returns also det[J] with J=[dx/du,..], that might be useful in gauss quadrature. More...

virtual double	GetDensity () override
	This is needed so that it can be accessed by ChLoaderVolumeGravity.

Public Member Functions inherited from chrono::fea::ChElementGeneric
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	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 void	ComputeNodalMass ()
	Compute element's nodal masses.

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

Public Member Functions inherited from chrono::ChLoadableUVW
virtual bool	IsTetrahedronIntegrationNeeded ()
	If true, use quadrature over u,v,w in [0..1] range as tetrahedron volumetric coords (with z=1-u-v-w) otherwise use default quadrature over u,v,w in [-1..+1] as box isoparametric coords.

virtual bool	IsTrianglePrismIntegrationNeeded ()
	If true, use quadrature over u,v in [0..1] range as triangle natural coords (with z=1-u-v), and use linear quadrature over w in [-1..+1], otherwise use default quadrature over u,v,w in [-1..+1] as box isoparametric coords.

Friends
class	Brick_ForceAnalytical

class	Brick_ForceNumerical

Additional Inherited Members
Protected Attributes inherited from chrono::fea::ChElementANCF
int	m_element_dof
	actual number of degrees of freedom for the element

bool	m_full_dof
	true if all node variables are active (not fixed)

ChArray< int >	m_mapping_dof
	indices of active DOFs (set only is some are fixed)

Protected Attributes inherited from chrono::fea::ChElementGeneric
ChKRMBlock	Kmatr

Member Function Documentation

◆ ComputeNF()

void chrono::fea::ChElementHexaANCF_3813::ComputeNF	(	const double	U,
		const double	V,
		const double	W,
		ChVectorDynamic<> &	Qi,
		double &	detJ,
		const ChVectorDynamic<> &	F,
		ChVectorDynamic<> *	state_x,
		ChVectorDynamic<> *	state_w
	)

overridevirtual

Evaluate N'*F , where N is some type of shape function evaluated at U,V,W coordinates of the volume, each ranging in -1..+1 F is a load, N'*F is the resulting generalized load Returns also det[J] with J=[dx/du,..], that might be useful in gauss quadrature.

Parameters

U	parametric coordinate in volume
V	parametric coordinate in volume
W	parametric coordinate in volume
Qi	Return result of N'*F here, maybe with offset block_offset
detJ	Return det[J] here
F	Input F vector, size is = n.field coords.
state_x	if != 0, update state (pos. part) to this, then evaluate Q
state_w	if != 0, update state (speed part) to this, then evaluate Q

Implements chrono::ChLoadableUVW.

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

/builds/uwsbel/chrono/src/chrono/fea/ChElementHexaANCF_3813.h
/builds/uwsbel/chrono/src/chrono/fea/ChElementHexaANCF_3813.cpp

Description

Public Types

Public Member Functions

Friends

Additional Inherited Members

Member Function Documentation

◆ ComputeNF()