chrono::fea::ChElementGeneric Class Reference

## Description

Class for all elements whose stiffness matrix can be seen as an NxN block-matrix split among N nodes.

Most FEA elements inherited from ChElementGeneric need to implement at most the two fundamental methods ComputeKRMmatricesGlobal(), ComputeInternalForces(), and optionally ComputeGravityForces().

#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
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 ComputeGravityForces (ChVectorDynamic<> &Fg, const ChVector<> &G_acc) override
Compute the gravitational forces. 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 GetNnodes ()=0
Get the number of nodes used by this element.

virtual int GetNdofs ()=0
Get the number of coordinates in the field used by the referenced nodes. More...

virtual int GetNdofs_active ()
Get the actual number of active degrees of freedom. More...

virtual int GetNodeNdofs (int n)=0
Get the number of coordinates from the specified node that are used by this element. 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 std::shared_ptr< ChNodeFEAbaseGetNodeN (int n)=0
Access the nth node.

virtual void GetStateBlock (ChVectorDynamic<> &mD)=0
Fill the D vector 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 (ChMatrixRef H, double Kfactor, double Rfactor=0, double Mfactor=0)=0
Set H as the stiffness matrix K, scaled by Kfactor. More...

virtual void ComputeInternalForces (ChVectorDynamic<> &Fi)=0
Compute the internal forces. More...

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

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

## Protected Attributes

ChKblockGeneric Kmatr

## ◆ ComputeGravityForces()

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

Compute the gravitational forces.

This default implementation (POTENTIALLY INEFFICIENT) uses a temporary ChLoaderGravity that applies the load to elements only if they are inherited by ChLoadableUVW so it can use GetDensity() and Gauss quadrature.

Implements chrono::fea::ChElementBase.

## ◆ ComputeMmatrixGlobal()

 void chrono::fea::ChElementGeneric::ComputeMmatrixGlobal ( ChMatrixRef M )
overridevirtual

Calculate the mass matrix, expressed in global reference.

This default implementation (POTENTIALLY VERY INEFFICIENT) should be overriden by derived classes a more efficient version.

Implements chrono::fea::ChElementBase.

 void chrono::fea::ChElementGeneric::EleIntLoadResidual_F_gravity ( ChVectorDynamic<> & R, const ChVector<> & G_acc, const double c )
overridevirtual

Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c This default implementation is VERY INEFFICIENT.

This fallback implementation uses a temp ChLoaderGravity that applies the load to elements only if they are inherited by ChLoadableUVW so it can use GetDensity() and Gauss quadrature.

Implements chrono::fea::ChElementBase.

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

Add 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.

The documentation for this class was generated from the following files:
• /builds/uwsbel/chrono/src/chrono/fea/ChElementGeneric.h
• /builds/uwsbel/chrono/src/chrono/fea/ChElementGeneric.cpp