Description

Classical Timoshenko beam element with two nodes, and tapered sections.

For this tapered beam element, the averaged section properties are used to formulate the mass, stiffness and damping matrices. Note that there are also ChElementCableANCF if no torsional effects are needed, as in cables.

#include <ChElementBeamTaperedTimoshenko.h>

Inheritance diagram for chrono::fea::ChElementBeamTaperedTimoshenko:

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Collaboration diagram for chrono::fea::ChElementBeamTaperedTimoshenko:

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Public Member Functions
virtual int	GetNnodes () override
	Get the number of nodes used by this element.

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

virtual int	GetNodeNdofs (int n) override
	Get the number of coordinates from the specified node that are used by this element. More...

virtual std::shared_ptr< ChNodeFEAbase >	GetNodeN (int n) override
	Access the nth node.

virtual void	SetNodes (std::shared_ptr< ChNodeFEAxyzrot > nodeA, std::shared_ptr< ChNodeFEAxyzrot > nodeB)

void	SetTaperedSection (std::shared_ptr< ChBeamSectionTaperedTimoshenkoAdvancedGeneric > my_material)
	Set the tapered section & material of beam element .

std::shared_ptr< ChBeamSectionTaperedTimoshenkoAdvancedGeneric >	GetTaperedSection ()
	Get the tapered section & material of the element.

std::shared_ptr< ChNodeFEAxyzrot >	GetNodeA ()
	Get the first node (beginning)

std::shared_ptr< ChNodeFEAxyzrot >	GetNodeB ()
	Get the second node (ending)

void	SetNodeAreferenceRot (ChQuaternion<> mrot)
	Set the reference rotation of nodeA respect to the element rotation.

ChQuaternion	GetNodeAreferenceRot ()
	Get the reference rotation of nodeA respect to the element rotation.

void	SetNodeBreferenceRot (ChQuaternion<> mrot)
	Set the reference rotation of nodeB respect to the element rotation.

ChQuaternion	GetNodeBreferenceRot ()
	Get the reference rotation of nodeB respect to the element rotation.

ChQuaternion	GetAbsoluteRotation ()
	Get the absolute rotation of element in space This is not the same of Rotation() , that expresses the accumulated rotation from starting point.

ChQuaternion	GetRefRotation ()
	Get the original reference rotation of element in space.

void	SetDisableCorotate (bool md)
	Set this as true to have the beam behave like a non-corotated beam hence do not update the corotated reference. More...

void	SetForceSymmetricStiffness (bool md)
	Set this as true to force the tangent stiffness matrix to be inexact, but symmetric. More...

void	SetUseGeometricStiffness (bool md)
	Set this as false to disable the contribution of geometric stiffness to the total tangent stiffness. More...

void	SetUseRc (bool md)
	Set this as true to include the transformation matrix due to the different elastic center offsets at two ends of beam element with respect to the centerline reference, in which case the connection line of two elastic centers is not parallel to the one of two centerline references at two ends. More...

void	SetUseRs (bool md)
	Set this as true to include the transformation matrix due to the different shear center offsets at two ends of beam element with respect to the centerline reference, in which case the connection line of two shear centers is not parallel to the one of two centerline references at two ends. More...

void	SetUseSimplifiedCorrectionForInclinedShearAxis (bool md)
	Set this as true to use a simplified correction model for the case of inclined shear axis. More...

void	ShapeFunctionsTimoshenko (ShapeFunctionGroup &NN, double eta)
	Shape functions for Timoshenko beam. More...

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

virtual void	UpdateRotation () override
	Compute large rotation of element for corotational approach The reference frame of this Euler-Bernoulli beam has X aligned to two nodes and Y parallel to Y of 1st node.

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

void	GetField_dt (ChVectorDynamic<> &mD_dt)
	Fills the Ddt vector with the current time derivatives of field values at the nodes of the element, with proper ordering. More...

void	GetField_dtdt (ChVectorDynamic<> &mD_dtdt)
	Fills the Ddtdt vector with the current time derivatives of field values at the nodes of the element, with proper ordering. More...

void	ComputeStiffnessMatrix ()
	Computes the local (material) stiffness matrix of the element: K = integral( [B]' * [D] * [B] ), Note: in this 'basic' implementation, constant section and constant material are assumed, so the explicit result of quadrature is used. More...

void	ComputeDampingMatrix ()
	Computes the local (material) damping matrix of the element: R = beta * integral( [B]' * [D] * [B] ), Note: in this 'basic' implementation, constant section and constant material are assumed, so the explicit result of quadrature is used. More...

void	ComputeGeometricStiffnessMatrix ()
	Computes the local geometric stiffness Kg of the element. More...

void	ComputeKiRimatricesLocal (bool inertial_damping, bool inertial_stiffness)
	Compute the inertia stiffness matrix [Ki^] and inertial damping matrix [Ri^] which are due to the gyroscopic effect.

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

virtual void	GetKRMmatricesLocal (ChMatrixRef H, double Kmfactor, double Kgfactor, double Rmfactor, double Mfactor)
	Gets the material mass, material stiffness, material damping and geometric stiffness matrices in local basis. More...

virtual void	ComputeInternalForces (ChVectorDynamic<> &Fi) override
	Computes the internal forces (e.g. More...

virtual void	ComputeInternalForces (ChVectorDynamic<> &Fi, bool Mfactor, bool Kfactor, bool Rfactor, bool Gfactor)
	Computes the inertial forces, damping forces, centrifugal forces and gyroscopic moments, then you could consider them as applied external forces, if you want to do the static solve when including nodal velocites and accelarations. More...

virtual void	ComputeGravityForces (ChVectorDynamic<> &Fg, const ChVector<> &G_acc) override
	Compute gravity forces, grouped in the Fg vector, one node after the other. More...

virtual void	EvaluateSectionDisplacement (const double eta, ChVector<> &u_displ, ChVector<> &u_rotaz) override
	Gets the xyz displacement of a point on the beam line, and the rotation RxRyRz of section plane, at abscyssa 'eta'. More...

virtual void	EvaluateSectionFrame (const double eta, ChVector<> &point, ChQuaternion<> &rot) override
	Gets the absolute xyz position of a point on the beam line, and the absolute rotation of section plane, at abscissa 'eta'. More...

virtual void	EvaluateSectionForceTorque (const double eta, ChVector<> &Fforce, ChVector<> &Mtorque) override
	Gets the force (traction x, shear y, shear z) and the torque (torsion on x, bending on y, on bending on z) at a section along the beam line, at abscissa 'eta'. More...

virtual void	EvaluateSectionStrain (const double eta, ChVector<> &StrainV) override
	Gets the axial and bending strain of the ANCF "cable" element.

virtual void	EvaluateSectionStrain (const double eta, ChVector<> &StrainV_trans, ChVector<> &StrainV_rot)
	Gets the strains(traction along x, shear along y, along shear z, torsion about x, bending about y, on bending about z) at a section along the beam line, at abscissa 'eta'. More...

virtual void	EvaluateElementStrainEnergy (ChVector<> &StrainEnergyV_trans, ChVector<> &StrainEnergyV_rot)
	Gets the elastic strain energy(traction along x, shear along y, along shear z, torsion about x, bending about y, on bending about z) in the element.

virtual void	EvaluateElementDampingEnergy (ChVector<> &DampingEnergyV_trans, ChVector<> &DampingEnergyV_rot)
	Gets the damping dissipated energy(traction along x, shear along y, along shear z, torsion about x, bending about y, on bending about z) in the element.

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

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

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

virtual void	LoadableGetStateBlock_w (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 int	Get_field_ncoords () override
	Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc.

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

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

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

virtual bool	IsSubBlockActive (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, 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 coordinates of the line, 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 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::ChElementBeam
double	GetMass ()
	The full mass of the beam, (with const. section, density, etc.)

double	GetRestLength ()
	The rest length of the bar.

void	SetRestLength (double ml)
	Set the rest length of the bar (usually this should be automatically done when SetupInitial is called on beams element, given the current state, but one might need to override this, ex for precompressed beams etc).

Public Member Functions inherited from chrono::fea::ChElementGeneric
ChKblockGeneric &	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	EleIntLoadResidual_F_gravity (ChVectorDynamic<> &R, const ChVector<> &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	ComputeMmatrixGlobal (ChMatrixRef M) override
	Calculate the mass matrix, expressed in global reference. More...

virtual void	InjectKRMmatrices (ChSystemDescriptor &descriptor) override
	Tell to a system descriptor that there are item(s) of type ChKblock in this object (for further passing it to a solver)

virtual void	KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor) override
	Add the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. 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 int	GetNdofs_active ()
	Get the actual number of active degrees of freedom. More...

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

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.

Public Member Functions inherited from chrono::fea::ChElementCorotational
ChMatrix33 &	Rotation ()
	Access the cumulative rotation matrix of the element. More...

Protected Member Functions
virtual void	SetupInitial (ChSystem *system) override
	Initial setup. More...

void	ComputeTransformMatrix ()
	compute the transformation matrix due to offset and rotation of axes.

void	ComputeTransformMatrixAtPoint (ChMatrixDynamic<> &mT, const double eta)
	compute the transformation matrix due to offset and rotation of axes, at dimensionless abscissa eta.

Protected Attributes
std::vector< std::shared_ptr< ChNodeFEAxyzrot > >	nodes

std::shared_ptr< ChBeamSectionTaperedTimoshenkoAdvancedGeneric >	tapered_section
	Tapered section & material of beam element.

ChMatrixDynamic	Km
	local material stiffness matrix

ChMatrixDynamic	Kg
	local geometric stiffness matrix NORMALIZED by P

ChMatrixDynamic	M
	local material mass matrix. More...

ChMatrixDynamic	Rm
	local material damping matrix

ChMatrixDynamic	Ri
	local inertial-damping (gyroscopic damping) matrix

ChMatrixDynamic	Ki
	local inertial-stiffness matrix

ChQuaternion	q_refrotA

ChQuaternion	q_refrotB

ChQuaternion	q_element_abs_rot

ChQuaternion	q_element_ref_rot

bool	disable_corotate

bool	force_symmetric_stiffness

bool	use_geometric_stiffness
	whether include geometric stiffness matrix

bool	use_Rc
	whether use the transformation matrix for elastic axis orientation

bool	use_Rs
	whether use the transformation matrix for shear axis orientation

bool	use_simplified_correction_for_inclined_shear_axis = false
	whether use the simplified correction model for shear axis orientation, it's false as default.

ChMatrixDynamic	T
	transformation matrix for entire beam element

ChMatrixDynamic	Rc
	transformation matrix for elastic axis orientation

ChMatrixDynamic	Rs
	transformation matrix for shear axis orientation

Protected Attributes inherited from chrono::fea::ChElementBeam
double	mass

double	length

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

Protected Attributes inherited from chrono::fea::ChElementCorotational
ChMatrix33	A

Member Function Documentation

◆ ComputeDampingMatrix()

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeDampingMatrix ( )

Computes the local (material) damping matrix of the element: R = beta * integral( [B]' * [D] * [B] ), Note: in this 'basic' implementation, constant section and constant material are assumed, so the explicit result of quadrature is used.

Also, this local material damping matrix is constant, computed only at the beginning for performance reasons; if you later change some material property, call this or InitialSetup(). Only the stiffness term(beta) is used for this implemented Rayleigh damping model.

◆ ComputeGeometricStiffnessMatrix()

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeGeometricStiffnessMatrix ( )

Computes the local geometric stiffness Kg of the element.

Note: this->Kg will be set as the geometric stiffness EXCLUDING the multiplication by the P pull force, in fact P multiplication happens in all terms, thus this allows making the Kg as a constant matrix that is computed only at the beginning, and later it is multiplied by P all times the real Kg is needed. If you later change some material property, call this or InitialSetup().

◆ ComputeGravityForces()

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeGravityForces	(	ChVectorDynamic<> &	Fg,
		const ChVector<> &	G_acc
	)

overridevirtual

Compute gravity forces, grouped in the Fg vector, one node after the other.

TODO for the lumped mass matrix case, the mM * mG product can be unrolled into few multiplications as mM mostly zero, and same for mG

Reimplemented from chrono::fea::ChElementGeneric.

◆ ComputeInternalForces() [1/2]

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

overridevirtual

Computes the internal forces (e.g.

the actual position of nodes is not in relaxed reference position) and set values in the Fi vector. This functionality can be used to output the forces and torques at two nodes directly.

Implements chrono::fea::ChElementBase.

◆ ComputeInternalForces() [2/2]

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeInternalForces	(	ChVectorDynamic<> &	Fi,
		bool	Mfactor,
		bool	Kfactor,
		bool	Rfactor,
		bool	Gfactor
	)

virtual

Computes the inertial forces, damping forces, centrifugal forces and gyroscopic moments, then you could consider them as applied external forces, if you want to do the static solve when including nodal velocites and accelarations.

Strictly speaking, it is not static solve any more. We can name it as quasi-static equilibrium solving, just the same as Simpack. It is recommended to use ChStaticNonLinearRheonomicAnalysis to do this kind of quasi-static equilibrium solving in case of rotating beams.

◆ ComputeKRMmatricesGlobal()

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

overridevirtual

Sets H as the global stiffness matrix K, scaled by Kfactor.

Optionally, also superimposes global damping matrix R, scaled by Rfactor, and global mass matrix M multiplied by Mfactor.

< current angular velocity of section of node A, in material frame

< current angular acceleration of section of node A, in material frame

< current acceleration of section of node A, in material frame)

< current angular velocity of section of node B, in material frame

< current angular acceleration of section of node B, in material frame

< current acceleration of section of node B, in material frame

Implements chrono::fea::ChElementBase.

◆ ComputeNF() [1/2]

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeNF	(	const double	U,
		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 coordinates of the line, 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 line
Qi	Return result of Q = N'*F here
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::ChLoadableU.

Reimplemented in chrono::fea::ChElementBeamTaperedTimoshenkoFPM.

◆ ComputeNF() [2/2]

void chrono::fea::ChElementBeamTaperedTimoshenko::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.

Reimplemented in chrono::fea::ChElementBeamTaperedTimoshenkoFPM.

◆ ComputeStiffnessMatrix()

void chrono::fea::ChElementBeamTaperedTimoshenko::ComputeStiffnessMatrix ( )

Computes the local (material) stiffness matrix of the element: K = integral( [B]' * [D] * [B] ), Note: in this 'basic' implementation, constant section and constant material are assumed, so the explicit result of quadrature is used.

Also, this local material stiffness matrix is constant, computed only at the beginning for performance reasons; if you later change some material property, call this or InitialSetup().

◆ EvaluateSectionDisplacement()

void chrono::fea::ChElementBeamTaperedTimoshenko::EvaluateSectionDisplacement	(	const double	eta,
		ChVector<> &	u_displ,
		ChVector<> &	u_rotaz
	)

overridevirtual

Gets the xyz displacement of a point on the beam line, and the rotation RxRyRz of section plane, at abscyssa 'eta'.

Note, eta=-1 at node1, eta=+1 at node2. Results are not corotated.

Implements chrono::fea::ChElementBeam.

Reimplemented in chrono::fea::ChElementBeamTaperedTimoshenkoFPM.

◆ EvaluateSectionForceTorque()

void chrono::fea::ChElementBeamTaperedTimoshenko::EvaluateSectionForceTorque	(	const double	eta,
		ChVector<> &	Fforce,
		ChVector<> &	Mtorque
	)

overridevirtual

Gets the force (traction x, shear y, shear z) and the torque (torsion on x, bending on y, on bending on z) at a section along the beam line, at abscissa 'eta'.

Note, eta=-1 at node1, eta=+1 at node2. Results are not corotated, and are expressed in the reference system of beam.

Implements chrono::fea::ChElementBeam.

Reimplemented in chrono::fea::ChElementBeamTaperedTimoshenkoFPM.

◆ EvaluateSectionFrame()

void chrono::fea::ChElementBeamTaperedTimoshenko::EvaluateSectionFrame	(	const double	eta,
		ChVector<> &	point,
		ChQuaternion<> &	rot
	)

overridevirtual

Gets the absolute xyz position of a point on the beam line, and the absolute rotation of section plane, at abscissa 'eta'.

Note, eta=-1 at node1, eta=+1 at node2. Results are corotated (expressed in world reference)

Implements chrono::fea::ChElementBeam.

◆ EvaluateSectionStrain()

void chrono::fea::ChElementBeamTaperedTimoshenko::EvaluateSectionStrain	(	const double	eta,
		ChVector<> &	StrainV_trans,
		ChVector<> &	StrainV_rot
	)

virtual

Gets the strains(traction along x, shear along y, along shear z, torsion about x, bending about y, on bending about z) at a section along the beam line, at abscissa 'eta'.

It's evaluated at the elastic center. Note, eta=-1 at node1, eta=+1 at node2. Results are not corotated, and are expressed in the reference system of beam.

Reimplemented in chrono::fea::ChElementBeamTaperedTimoshenkoFPM.

◆ GetField_dt()

void chrono::fea::ChElementBeamTaperedTimoshenko::GetField_dt ( ChVectorDynamic<> & mD_dt )

Fills the Ddt vector with the current time derivatives of field values at the nodes of the element, with proper ordering.

If the D vector has not the size of this->GetNdofs(), it will be resized. For corotational elements, field is assumed in local reference! Give that this element includes rotations at nodes, this gives: {v_a v_a v_a wx_a wy_a wz_a v_b v_b v_b wx_b wy_b wz_b}

◆ GetField_dtdt()

void chrono::fea::ChElementBeamTaperedTimoshenko::GetField_dtdt ( ChVectorDynamic<> & mD_dtdt )

Fills the Ddtdt vector with the current time derivatives of field values at the nodes of the element, with proper ordering.

If the D vector has not the size of this->GetNdofs(), it will be resized. For corotational elements, field is assumed in local reference! Give that this element includes rotations at nodes, this gives: {acc_a acc_a acc_a accx_a accy_a accz_a acc_b acc_b acc_b accx_b accy_b accz_b}

◆ GetKRMmatricesLocal()

void chrono::fea::ChElementBeamTaperedTimoshenko::GetKRMmatricesLocal	(	ChMatrixRef	H,
		double	Kmfactor,
		double	Kgfactor,
		double	Rmfactor,
		double	Mfactor
	)

virtual

Gets the material mass, material stiffness, material damping and geometric stiffness matrices in local basis.

This functionality can be used to output these matrices for some other special needs.

◆ GetNdofs()

virtual int chrono::fea::ChElementBeamTaperedTimoshenko::GetNdofs ( )

inlineoverridevirtual

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.

Implements chrono::fea::ChElementBase.

◆ GetNodeNdofs()

virtual int chrono::fea::ChElementBeamTaperedTimoshenko::GetNodeNdofs ( int n )

inlineoverridevirtual

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 GetNodeN(n)->GetNdofW().

Implements chrono::fea::ChElementBase.

◆ GetStateBlock()

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

overridevirtual

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

If the D vector has not the size of this->GetNdofs(), it will be resized. For corotational elements, field is assumed in local reference! Given that this element includes rotations at nodes, this gives: {x_a y_a z_a Rx_a Ry_a Rz_a x_b y_b z_b Rx_b Ry_b Rz_b}

Implements chrono::fea::ChElementBase.

◆ SetDisableCorotate()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetDisableCorotate ( bool md )

inline

Set this as true to have the beam behave like a non-corotated beam hence do not update the corotated reference.

Just for benchmarks!

◆ SetForceSymmetricStiffness()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetForceSymmetricStiffness ( bool md )

inline

Set this as true to force the tangent stiffness matrix to be inexact, but symmetric.

This allows the use of faster solvers. For systems close to the equilibrium, the tangent stiffness would be symmetric anyway.

◆ SetupInitial()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetupInitial ( ChSystem * system )

overrideprotectedvirtual

Initial setup.

Precompute mass and matrices that do not change during the simulation, such as the local tangent stiffness Kl of each element, if needed, etc.

Reimplemented from chrono::fea::ChElementBase.

◆ SetUseGeometricStiffness()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetUseGeometricStiffness ( bool md )

inline

Set this as false to disable the contribution of geometric stiffness to the total tangent stiffness.

By default it is on.

◆ SetUseRc()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetUseRc ( bool md )

inline

Set this as true to include the transformation matrix due to the different elastic center offsets at two ends of beam element with respect to the centerline reference, in which case the connection line of two elastic centers is not parallel to the one of two centerline references at two ends.

By default it is on. Please refer to ANSYS theory document for more information.

◆ SetUseRs()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetUseRs ( bool md )

inline

Set this as true to include the transformation matrix due to the different shear center offsets at two ends of beam element with respect to the centerline reference, in which case the connection line of two shear centers is not parallel to the one of two centerline references at two ends.

By default it is on. This transformation matrix could decrease the equivalent torsional stiffness of beam element, and hence generate larger torsional rotation. Please refer to ANSYS theory document for more information.

◆ SetUseSimplifiedCorrectionForInclinedShearAxis()

void chrono::fea::ChElementBeamTaperedTimoshenko::SetUseSimplifiedCorrectionForInclinedShearAxis ( bool md )

inline

Set this as true to use a simplified correction model for the case of inclined shear axis.

By default it is false. This option may affect the bending-twist coupling of Timoshenko beam element, especially when the inclined angle of shear center axis is obvious with respect to the centerline.

◆ ShapeFunctionsTimoshenko()

void chrono::fea::ChElementBeamTaperedTimoshenko::ShapeFunctionsTimoshenko	(	ShapeFunctionGroup &	NN,
		double	eta
	)

Shape functions for Timoshenko beam.

Please refer to the textbook: J. S. Przemieniecki, Theory of Matrix Structural Analysis-Dover Publications (1985).

◆ Update()

void chrono::fea::ChElementBeamTaperedTimoshenko::Update ( )

overridevirtual

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.

Reimplemented from chrono::fea::ChElementBase.

Member Data Documentation

◆ M

ChMatrixDynamic chrono::fea::ChElementBeamTaperedTimoshenko::M

protected

local material mass matrix.

It could be lumped or consistent mass matrix, depending on SetLumpedMassMatrix(true/false)

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

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

Description

Public Member Functions

Protected Member Functions

Protected Attributes

Member Function Documentation

◆ ComputeDampingMatrix()

◆ ComputeGeometricStiffnessMatrix()

◆ ComputeGravityForces()

◆ ComputeInternalForces() [1/2]

◆ ComputeInternalForces() [2/2]

◆ ComputeKRMmatricesGlobal()

◆ ComputeNF() [1/2]

◆ ComputeNF() [2/2]

◆ ComputeStiffnessMatrix()

◆ EvaluateSectionDisplacement()

◆ EvaluateSectionForceTorque()

◆ EvaluateSectionFrame()

◆ EvaluateSectionStrain()

◆ GetField_dt()

◆ GetField_dtdt()

◆ GetKRMmatricesLocal()

◆ GetNdofs()

◆ GetNodeNdofs()

◆ GetStateBlock()

◆ SetDisableCorotate()

◆ SetForceSymmetricStiffness()

◆ SetupInitial()

◆ SetUseGeometricStiffness()

◆ SetUseRc()

◆ SetUseRs()

◆ SetUseSimplifiedCorrectionForInclinedShearAxis()

◆ ShapeFunctionsTimoshenko()

◆ Update()

Member Data Documentation

◆ M