chrono::ChLoad< Tloader > Class Template Reference

Description

template<class Tloader>
class chrono::ChLoad< Tloader >

Class for a load acting on a single ChLoadable item, via ChLoader objects.

There are various ChLoader interfaces ready to use, that can be used as 'building blocks'. These are expecially important for creating loads that are distributed on surfaces, lines, volumes, since some ChLoaders implement quadrature. Create them as ChLoad< ChLoaderPressure > my_load(...); for example.

#include <ChLoad.h>

Inheritance diagram for chrono::ChLoad< Tloader >:
Collaboration diagram for chrono::ChLoad< Tloader >:

Public Member Functions

 ChLoad (std::shared_ptr< typename Tloader::type_loadable > mloadable)
 
virtual int LoadGet_ndof_x ()
 Gets the number of DOFs affected by this load (position part)
 
virtual int LoadGet_ndof_w ()
 Gets the number of DOFs affected by this load (speed part)
 
virtual void LoadGetStateBlock_x (ChState &mD)
 Gets all the current DOFs packed in a single vector (position part)
 
virtual void LoadGetStateBlock_w (ChStateDelta &mD)
 Gets all the current DOFs packed in a single vector (speed part)
 
virtual void LoadStateIncrement (const ChState &x, const ChStateDelta &dw, ChState &x_new)
 Increment a packed state (ex. More...
 
virtual int LoadGet_field_ncoords ()
 Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc. More...
 
virtual void ComputeQ (ChState *state_x, ChStateDelta *state_w)
 Compute Q, the generalized load. More...
 
virtual void ComputeJacobian (ChState *state_x, ChStateDelta *state_w, ChMatrix<> &mK, ChMatrix<> &mR, ChMatrix<> &mM)
 Compute jacobians (default fallback). More...
 
virtual void LoadIntLoadResidual_F (ChVectorDynamic<> &R, const double c)
 Adds the internal loads Q (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += forces * c.
 
virtual bool IsStiff ()
 Default: load is stiff if the loader is stiff. Override if needed.
 
virtual void CreateJacobianMatrices ()
 Create the jacobian loads if needed, and also set the ChVariables referenced by the sparse KRM block. More...
 
- Public Member Functions inherited from chrono::ChLoadBase
ChLoadJacobiansGetJacobians ()
 Access the jacobians (if any, i.e. if this is a stiff load)
 
virtual void Update ()
 Update: this is called at least at each time step. More...
 
virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor)
 Tell to a system descriptor that there are item(s) of type ChKblock in this object (for further passing it to a solver) Basically does nothing, but inherited classes must specialize this. More...
 
virtual void KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor)
 Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. More...
 

Public Attributes

Tloader loader
 

Additional Inherited Members

- Protected Attributes inherited from chrono::ChLoadBase
ChLoadJacobiansjacobians
 

Member Function Documentation

template<class Tloader>
virtual void chrono::ChLoad< Tloader >::ComputeJacobian ( ChState state_x,
ChStateDelta state_w,
ChMatrix<> &  mK,
ChMatrix<> &  mR,
ChMatrix<> &  mM 
)
virtual

Compute jacobians (default fallback).

Uses a numerical differentiation for computing K, R, M jacobians, if stiff load. If possible, override this with an analytical jacobian. Compute the K=-dQ/dx, R=-dQ/dv , M=-dQ/da jacobians. Called automatically at each Update().

Parameters
state_xstate position to evaluate jacobians
state_wstate speed to evaluate jacobians
mKresult dQ/dx
mRresult dQ/dv
mMresult dQ/da

Implements chrono::ChLoadBase.

template<class Tloader>
virtual void chrono::ChLoad< Tloader >::ComputeQ ( ChState state_x,
ChStateDelta state_w 
)
virtual

Compute Q, the generalized load.

Q is stored in the wrapped ChLoader. Called automatically at each Update().

Parameters
state_xstate position to evaluate Q
state_wstate speed to evaluate Q

Implements chrono::ChLoadBase.

template<class Tloader>
virtual void chrono::ChLoad< Tloader >::CreateJacobianMatrices ( )
virtual

Create the jacobian loads if needed, and also set the ChVariables referenced by the sparse KRM block.

Implements chrono::ChLoadBase.

template<class Tloader>
virtual int chrono::ChLoad< Tloader >::LoadGet_field_ncoords ( )
virtual

Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc.

Implements chrono::ChLoadBase.

template<class Tloader>
virtual void chrono::ChLoad< Tloader >::LoadStateIncrement ( const ChState x,
const ChStateDelta dw,
ChState x_new 
)
virtual

Increment a packed state (ex.

as obtained by LoadGetStateBlock_x()) by a given packed state-delta. Compute: x_new = x + dw. Ex. this is called by the BDF numerical differentiation routine that computes jacobian in the default ComputeJacobian() fallback, if not overriding ComputeJacobian() with an analytical form.

Implements chrono::ChLoadBase.