chrono::fea::ChElementGeneric Class Reference

## Description

Class for all elements whose stiffness matrix can be seen as a NxN block-matrix to be splitted between N nodes.

Helps reducing the complexity of inherited FEA elements because it implements some bookkeeping for the interface with solver. This means that most FEA elements inherited from ChElementGeneric need to implement at most the following two fundamental methods: ComputeKRMmatricesGlobal(), ComputeInternalForces()

#include <ChElementGeneric.h>

Inheritance diagram for chrono::fea::ChElementGeneric:
Collaboration diagram for chrono::fea::ChElementGeneric:

## Public Member Functions

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< ChNodeFEAbaseGetNodeN (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...

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

## Protected Attributes

ChKblockGeneric Kmatr

## Member Function Documentation

 virtual void chrono::fea::ChElementGeneric::ComputeMmatrixGlobal ( ChMatrix<> & M )
overridevirtual

Returns the global mass matrix.

This is the default implementation, POTENTIALLY VERY INEFFICIENT. Children classes may need to override this with a more efficient version.

Implements chrono::fea::ChElementBase.

 virtual void chrono::fea::ChElementGeneric::KRMmatricesLoad ( double Kfactor, double Rfactor, double Mfactor )
overridevirtual

Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any.

The K, R, M matrices are load with scaling values Kfactor, Rfactor, Mfactor.

Implements chrono::fea::ChElementBase.

 void chrono::fea::ChElementGeneric::VariablesFbIncrementMq ( )
overridevirtual

Adds M*q (internal masses multiplied current 'qb') to Fb, ex.

if qb is initialized with v_old using VariablesQbLoadSpeed, this method can be used in timestepping schemes that do: M*v_new = M*v_old + forces*dt (This is a default (VERY UNOPTIMAL) book keeping so that in children classes you can avoid implementing this VariablesFbIncrementMq function, unless you need faster code.)

Reimplemented from chrono::fea::ChElementBase.