chrono::fea::ChElementBeam Class Referenceabstract

Description

Base class for most structral elements of 'beam' type.

#include <ChElementBeam.h>

Inheritance diagram for chrono::fea::ChElementBeam:
Collaboration diagram for chrono::fea::ChElementBeam:

Public Member Functions

virtual void EvaluateSectionDisplacement (const double eta, const ChMatrix<> &displ, ChVector<> &u_displ, ChVector<> &u_rotaz)=0
 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, const ChMatrix<> &displ, ChVector<> &point, ChQuaternion<> &rot)=0
 Gets the absolute xyz position of a point on the beam line, and the absolute rotation of section plane, at abscyssa 'eta'. More...
 
virtual void EvaluateSectionForceTorque (const double eta, const ChMatrix<> &displ, ChVector<> &Fforce, ChVector<> &Mtorque)=0
 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 abscyssa 'eta'. More...
 
virtual void EvaluateSectionStrain (const double eta, const ChMatrix<> &displ, ChVector<> &StrainV)=0
 Gets the axial and bending strain of the ANCF "cable" element.
 
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 (ususlly 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 int GetNnodes ()=0
 Gets the number of nodes used by this element.
 
virtual int GetNdofs ()=0
 Gets the number of coordinates in the field used by the referenced nodes. More...
 
virtual int GetNodeNdofs (int n)=0
 Get the number of coordinates from the n-th node that are used by this element. More...
 
virtual std::shared_ptr
< ChNodeFEAbase
GetNodeN (int n)=0
 Access the nth node.
 
virtual void GetStateBlock (ChMatrixDynamic<> &mD)=0
 Fills the D vector (column matrix) 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 (ChMatrix<> &H, double Kfactor, double Rfactor=0, double Mfactor=0)=0
 Sets H as the stiffness matrix K, scaled by Kfactor. More...
 
virtual void ComputeInternalForces (ChMatrixDynamic<> &Fi)=0
 Computes the internal forces (ex. More...
 
virtual void SetupInitial (ChSystem *system)
 Initial setup: This is used mostly to precompute matrices that do not change during the simulation, i.e. More...
 
virtual void Update ()
 Update: this is called at least at each time step. More...
 

Protected Attributes

double mass
 
double length
 
- Protected Attributes inherited from chrono::fea::ChElementGeneric
ChKblockGeneric Kmatr
 

Member Function Documentation

virtual void chrono::fea::ChElementBeam::EvaluateSectionDisplacement ( const double  eta,
const ChMatrix<> &  displ,
ChVector<> &  u_displ,
ChVector<> &  u_rotaz 
)
pure virtual

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.

Implemented in chrono::fea::ChElementBeamEuler, chrono::fea::ChElementCableANCF, and chrono::fea::ChElementBeamANCF.

virtual void chrono::fea::ChElementBeam::EvaluateSectionForceTorque ( const double  eta,
const ChMatrix<> &  displ,
ChVector<> &  Fforce,
ChVector<> &  Mtorque 
)
pure virtual

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 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, and are expressed in the reference system of beam.

Implemented in chrono::fea::ChElementBeamEuler, and chrono::fea::ChElementCableANCF.

virtual void chrono::fea::ChElementBeam::EvaluateSectionFrame ( const double  eta,
const ChMatrix<> &  displ,
ChVector<> &  point,
ChQuaternion<> &  rot 
)
pure virtual

Gets the absolute xyz position of a point on the beam line, and the absolute rotation 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 corotated.

Implemented in chrono::fea::ChElementBeamEuler, chrono::fea::ChElementCableANCF, and chrono::fea::ChElementBeamANCF.

void chrono::fea::ChElementBeam::SetRestLength ( double  ml)

Set the rest length of the bar (ususlly 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).