chrono::fea::ChElementBeamIGA Class Reference

Description

Element of IGA type, with Timoshenko shear etc.

et.. etc. (intro to write) Note: each IGA element represents one "knot span" of the spline!

#include <ChElementBeamIGA.h>

Inheritance diagram for chrono::fea::ChElementBeamIGA:
Collaboration diagram for chrono::fea::ChElementBeamIGA:

Public Member Functions

virtual int GetNnodes () override
 Gets the number of nodes used by this element.
 
virtual int GetNdofs () override
 Gets 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 n-th node that are used by this element. More...
 
virtual std::shared_ptr< ChNodeFEAbaseGetNodeN (int n) override
 Access the nth node.
 
virtual void SetNodesCubic (std::shared_ptr< ChNodeFEAxyzrot > nodeA, std::shared_ptr< ChNodeFEAxyzrot > nodeB, std::shared_ptr< ChNodeFEAxyzrot > nodeC, std::shared_ptr< ChNodeFEAxyzrot > nodeD, double knotA1, double knotA2, double knotB1, double knotB2, double knotB3, double knotB4, double knotB5, double knotB6)
 
virtual void SetNodesGenericOrder (std::vector< std::shared_ptr< ChNodeFEAxyzrot >> mynodes, std::vector< double > myknots, int myorder)
 
void SetIntegrationPoints (int npoints_s, int npoints_b)
 Set the integration points, for shear components and for bending components:
 
void SetSection (std::shared_ptr< ChBeamSectionCosserat > my_material)
 Set the section & material of beam element . More...
 
std::shared_ptr< ChBeamSectionCosseratGetSection ()
 Get the section & material of the element.
 
ChVectorDynamicGetKnotSequence ()
 Access the local knot sequence of this element (ex.for diagnostics)
 
virtual void Update () override
 Update: this is called at least at each time step. More...
 
std::vector< std::unique_ptr< ChBeamMaterialInternalData > > & GetPlasticData ()
 Get the plastic data, in a vector with as many elements as Gauss points.
 
std::vector< ChVector<> > & GetStressN ()
 Get the stress, as cut-force [N], in a vector with as many elements as Gauss points.
 
std::vector< ChVector<> > & GetStressM ()
 Get the stress, as cut-torque [Nm], in a vector with as many elements as Gauss points.
 
std::vector< ChVector<> > & GetStrainE ()
 Get the strain (total=elastic+plastic), as deformation (x is axial strain), in a vector with as many elements as Gauss points.
 
std::vector< ChVector<> > & GetStrainK ()
 Get the strain (total=elastic+plastic), as curvature (x is torsion), in a vector with as many elements as Gauss points.
 
virtual void SetupInitial (ChSystem *system) override
 Setup. More...
 
virtual void GetStateBlock (ChMatrixDynamic<> &mD) override
 Fills the D vector (column matrix) 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.
 
virtual void ComputeKRMmatricesGlobal (ChMatrix<> &H, double Kfactor, double Rfactor=0, double Mfactor=0) override
 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.
 
virtual void ComputeInternalForces (ChMatrixDynamic<> &Fi) override
 Computes the internal forces (ex. the actual position of nodes is not in relaxed reference position) and set values in the Fi vector.
 
virtual void ComputeInternalForces_impl (ChMatrixDynamic<> &Fi, ChState &state_x, ChStateDelta &state_w, bool used_for_differentiation=false)
 
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'. Note, eta=-1 at node1, eta=+1 at node2. Note, 'displ' is the displ.state of 2 nodes, ex. get it as GetStateBlock() Results are not corotated.
 
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'. Note, eta=-1 at node1, eta=+1 at node2. Note, 'displ' is the displ.state of 2 nodes, ex. get it as GetStateBlock() Results are corotated (expressed in world reference) 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'. Note, eta=-1 at node1, eta=+1 at node2. Note, 'displ' is the displ.state of 2 nodes, ex. get it as GetStateBlock(). Results are not corotated, and are expressed in the reference system of beam.
 
virtual void EvaluateSectionStrain (const double eta, ChVector<> &StrainV) override
 Gets the axial and bending strain of the ANCF "cable" element.
 
virtual void EleDoIntegration () override
 This is optionally implemented if there is some internal state that requires integration. More...
 
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
 Tell the number of DOFs blocks (ex. =1 for a body, =4 for a tetrahedron, etc.)
 
virtual unsigned int GetSubBlockOffset (int nblock) override
 Get the offset of the i-th sub-block of DOFs in global vector.
 
virtual unsigned int GetSubBlockSize (int nblock) override
 Get the size of the i-th sub-block of DOFs in global vector.
 
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, 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). More...
 
- Public Member Functions inherited from chrono::fea::ChElementGeneric
ChKblockGenericKstiffness ()
 Access the proxy to stiffness, for sparse solver.
 
virtual void EleIntLoadResidual_F (ChVectorDynamic<> &R, const double c) override
 (This is a default (a bit unoptimal) book keeping so that in children classes you can avoid implementing this EleIntLoadResidual_F function, unless you need faster code)
 
virtual void EleIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
 (This is a default (VERY UNOPTIMAL) book keeping so that in children classes you can avoid implementing this EleIntLoadResidual_Mv function, unless you need faster code.)
 
virtual void ComputeMmatrixGlobal (ChMatrix<> &M) override
 Returns the global mass matrix. More...
 
virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor) 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
 Adds 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
 Adds the internal forces, expressed as nodal forces, into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor (This is a default (a bit unoptimal) book keeping so that in children classes you can avoid implementing this VariablesFbLoadInternalForces function, unless you need faster code)
 
virtual void VariablesFbIncrementMq () override
 Adds M*q (internal masses multiplied current 'qb') to Fb, ex. More...
 
- Public Member Functions inherited from chrono::fea::ChElementBase
virtual void ComputeNodalMass ()
 Compute element's nodal masses.
 
- 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 quadrature over u,v,w in [-1..+1] as box isoparametric coords. More...
 

Protected Attributes

std::vector< std::shared_ptr< ChNodeFEAxyzrot > > nodes
 
ChVectorDynamic knots
 
int order
 
int int_order_s
 
int int_order_b
 
std::vector< double > Jacobian_s
 
std::vector< double > Jacobian_b
 
std::vector< ChVector<> > strain_e_0
 
std::vector< ChVector<> > strain_k_0
 
std::vector< ChVector<> > stress_n
 
std::vector< ChVector<> > stress_m
 
std::vector< ChVector<> > strain_e
 
std::vector< ChVector<> > strain_k
 
std::vector< std::unique_ptr< ChBeamMaterialInternalData > > plastic_data_old
 
std::vector< std::unique_ptr< ChBeamMaterialInternalData > > plastic_data
 
std::shared_ptr< ChBeamSectionCosseratsection
 
- Protected Attributes inherited from chrono::fea::ChElementBeam
double mass
 
double length
 
- Protected Attributes inherited from chrono::fea::ChElementGeneric
ChKblockGeneric Kmatr
 

Member Function Documentation

virtual void chrono::fea::ChElementBeamIGA::ComputeInternalForces_impl ( ChMatrixDynamic<> &  Fi,
ChState state_x,
ChStateDelta state_w,
bool  used_for_differentiation = false 
)
virtual

< here return N and dN/du

Parameters
state_xstate position to evaluate Fi
state_wstate speed to evaluate Fi
virtual void chrono::fea::ChElementBeamIGA::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, 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.

< h

Parameters
Ueta parametric coordinate in line -1..+1
QiReturn result of Q = N'*F here
detJReturn det[J] here
FInput F vector, size is =n. field coords.
state_xif != 0, update state (pos. part) to this, then evaluate Q
state_wif != 0, update state (speed part) to this, then evaluate Q

Implements chrono::ChLoadableU.

virtual void chrono::fea::ChElementBeamIGA::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
Uparametric coordinate in volume
Vparametric coordinate in volume
Wparametric coordinate in volume
QiReturn result of N'*F here, maybe with offset block_offset
detJReturn det[J] here
FInput F vector, size is = n.field coords.
state_xif != 0, update state (pos. part) to this, then evaluate Q
state_wif != 0, update state (speed part) to this, then evaluate Q

Implements chrono::ChLoadableUVW.

virtual void chrono::fea::ChElementBeamIGA::EleDoIntegration ( )
overridevirtual

This is optionally implemented if there is some internal state that requires integration.

Reimplemented from chrono::fea::ChElementBase.

virtual void chrono::fea::ChElementBeamIGA::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. Note, 'displ' is the displ.state of 2 nodes, ex. get it as GetStateBlock() Results are corotated (expressed in world reference)

< here return in N

Implements chrono::fea::ChElementBeam.

virtual int chrono::fea::ChElementBeamIGA::GetNdofs ( )
overridevirtual

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

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

Implements chrono::fea::ChElementBase.

virtual int chrono::fea::ChElementBeamIGA::GetNodeNdofs ( int  n)
overridevirtual

Get the number of coordinates from the n-th node that are used by this element.

Note that this may be different from the value returned by GetNodeN(n)->Get_ndof_w();

Implements chrono::fea::ChElementBase.

void chrono::fea::ChElementBeamIGA::SetSection ( std::shared_ptr< ChBeamSectionCosserat my_material)

Set the section & material of beam element .

It is a shared property, so it can be shared between other beams.

virtual void chrono::fea::ChElementBeamIGA::SetupInitial ( ChSystem system)
overridevirtual

Setup.

Precompute mass and matrices that do not change during the simulation. In particular, compute the arc-length parametrization.

< here return N and dN/du

< here return N and dN/du

Reimplemented from chrono::fea::ChElementBase.

virtual void chrono::fea::ChElementBeamIGA::Update ( )
overridevirtual

Update: this is 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 is the proper place.

Reimplemented from chrono::fea::ChElementBase.