Description
For composite beams such as wind turbine blades and helicopter rotor blades, the cross-sectional stiffness properties in axial, shear, bending and torsion directions are coupled with each other, hence the fully-populated matrix(FPM) of cross-sectional stiffness properties is used to describe this complex coupling.
The shape functions of classical Timoshenko beam are not applicable for this new Timoshenko beam. In this tapered Timoshenko beam, the shape functions are numerically derived according to the cross-sectional fully-populated stiffness matrix(FPM), and the local mass, stiffness and damping matrices(M K R) are evaluated via Gauss quadrature. When the fully-populated stiffness matrix(FPM) includes only diagonal elements(no coupling in the cross-sectional stiffness matrix, such as a circular section made from steel), the shape functions are reduced to the occasion in classical Timoshenko beam as in ChElementBeamTaperedTimoshenko, then ChElementBeamTaperedTimoshenkoFPM is equal to ChElementBeamTaperedTimoshenko. Note that there are also ChElementCableANCF if no torsional effects are needed, as in cables.
#include <ChElementBeamTaperedTimoshenkoFPM.h>
Public Types | |
using | ShapeFunctionGroupFPM = std::tuple< ChMatrixNM< double, 6, 12 >, ChMatrixNM< double, 6, 12 > > |
Public Member Functions | |
void | SetTaperedSection (std::shared_ptr< ChBeamSectionTaperedTimoshenkoAdvancedGenericFPM > my_material) |
Set the tapered section & material of beam element. | |
std::shared_ptr< ChBeamSectionTaperedTimoshenkoAdvancedGenericFPM > | GetTaperedSection () |
Get the tapered section & material of the element. | |
void | ShapeFunctionsTimoshenkoFPM (ShapeFunctionGroupFPM &NB, double eta) |
Computes the shape function matrix 'Nx' and strain-displacement relation matrix 'Bx' at dimensionless abscissa 'eta'. More... | |
void | SetIntegrationPoints (int mv) |
Set the order of Gauss quadrature, as default it is four. | |
int | GetIntegrationPoints () |
Get the order of Gauss quadrature. | |
void | ComputeStiffnessMatrix () |
Computes the local (material) stiffness matrix of the element: K = integral( [B]' * [D] * [B] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam. More... | |
void | ComputeDampingMatrix () |
Computes the local element damping matrix via Guass Quadrature: R = beta * integral( [B]' * [D] * [B] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam. More... | |
void | ComputeConsistentMassMatrix () |
Computes the local element consistent mass matrix via Guass Quadrature: M = integral( [N]' * [D] * [N] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam. More... | |
void | ComputeMassMatrix () |
Finally, compute the local mass matrix of element. 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 | 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) override |
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 | 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... | |
Public Member Functions inherited from chrono::fea::ChElementBeamTaperedTimoshenko | |
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 | 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 | 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 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... | |
Additional Inherited Members | |
Protected Member Functions inherited from chrono::fea::ChElementBeamTaperedTimoshenko | |
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 inherited from chrono::fea::ChElementBeamTaperedTimoshenko | |
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
◆ ComputeConsistentMassMatrix()
void chrono::fea::ChElementBeamTaperedTimoshenkoFPM::ComputeConsistentMassMatrix | ( | ) |
Computes the local element consistent mass matrix via Guass Quadrature: M = integral( [N]' * [D] * [N] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam.
Also, this local element consistent mass matrix is constant, computed only at the beginning for performance reasons; if you later change some material property, call this or InitialSetup().
◆ ComputeDampingMatrix()
void chrono::fea::ChElementBeamTaperedTimoshenkoFPM::ComputeDampingMatrix | ( | ) |
Computes the local element damping matrix via Guass Quadrature: R = beta * integral( [B]' * [D] * [B] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam.
Only the stiffness term(beta) is used for this implemented Rayleigh damping model. 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().
◆ ComputeMassMatrix()
void chrono::fea::ChElementBeamTaperedTimoshenkoFPM::ComputeMassMatrix | ( | ) |
Finally, compute the local mass matrix of element.
It could be in lumped or consistent format, depending on the parameter 'use_lumped_mass_matrix' in its sectional settings.
◆ ComputeNF() [1/2]
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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
Reimplemented from chrono::fea::ChElementBeamTaperedTimoshenko.
◆ ComputeNF() [2/2]
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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
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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
Reimplemented from chrono::fea::ChElementBeamTaperedTimoshenko.
◆ ComputeStiffnessMatrix()
void chrono::fea::ChElementBeamTaperedTimoshenkoFPM::ComputeStiffnessMatrix | ( | ) |
Computes the local (material) stiffness matrix of the element: K = integral( [B]' * [D] * [B] ), Note: the sectional properties at Gauss integration point are linearly interpolated from two ends of tapered beam.
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()
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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.
Reimplemented from chrono::fea::ChElementBeamTaperedTimoshenko.
◆ EvaluateSectionForceTorque()
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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.
Reimplemented from chrono::fea::ChElementBeamTaperedTimoshenko.
◆ EvaluateSectionStrain()
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overridevirtual |
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 from chrono::fea::ChElementBeamTaperedTimoshenko.
◆ ShapeFunctionsTimoshenkoFPM()
void chrono::fea::ChElementBeamTaperedTimoshenkoFPM::ShapeFunctionsTimoshenkoFPM | ( | ShapeFunctionGroupFPM & | NB, |
double | eta | ||
) |
Computes the shape function matrix 'Nx' and strain-displacement relation matrix 'Bx' at dimensionless abscissa 'eta'.
Note, eta=-1 at node1, eta=+1 at node2.
- Parameters
-
NB shape function matrix 'Nx' and strain-displacement relation matrix 'Bx' are stored here. eta abscissa 'eta'. eta=-1 at node1, eta=+1 at node2.
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono/fea/ChElementBeamTaperedTimoshenkoFPM.h
- /builds/uwsbel/chrono/src/chrono/fea/ChElementBeamTaperedTimoshenkoFPM.cpp