Description
Base class for loads.
This class can be inherited to implement applied loads to bodies, finite elements, etc. A load is an object that might wrap one or more ChLoader objects, whose value is dependent. It implements functionalities to perform automatic differentiation of the load so it optionally can compute the jacobian (the tangent stiffness matrix of the load) that can be used in implicit integrators, statics, etc.
#include <ChLoad.h>
Public Member Functions | |
virtual int | LoadGet_ndof_x ()=0 |
Gets the number of DOFs affected by this load (position part) | |
virtual int | LoadGet_ndof_w ()=0 |
Gets the number of DOFs affected by this load (speed part) | |
virtual void | LoadGetStateBlock_x (ChState &mD)=0 |
Gets all the current DOFs packed in a single vector (position part) | |
virtual void | LoadGetStateBlock_w (ChStateDelta &mD)=0 |
Gets all the current DOFs packed in a single vector (speed part) | |
virtual void | LoadStateIncrement (const ChState &x, const ChStateDelta &dw, ChState &x_new)=0 |
Increment a packed state (ex. More... | |
virtual int | LoadGet_field_ncoords ()=0 |
Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc. | |
virtual void | ComputeQ (ChState *state_x, ChStateDelta *state_w)=0 |
Compute Q, the generalized load(s). More... | |
virtual void | ComputeJacobian (ChState *state_x, ChStateDelta *state_w, ChMatrixRef mK, ChMatrixRef mR, ChMatrixRef mM)=0 |
Compute the K=-dQ/dx, R=-dQ/dv , M=-dQ/da jacobians. More... | |
ChLoadJacobians * | GetJacobians () |
Access the jacobians (if any, i.e. if this is a stiff load) | |
virtual void | CreateJacobianMatrices ()=0 |
Create the jacobian loads if needed, and also set the ChVariables referenced by the sparse KRM block. | |
virtual void | Update (double time) |
Update: this is called at least at each time step. More... | |
virtual bool | IsStiff ()=0 |
Report if this is load is stiff. More... | |
virtual void | LoadIntLoadResidual_F (ChVectorDynamic<> &R, double c)=0 |
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 void | LoadIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, double c)=0 |
Increment a vector R with a term that has M multiplied a given vector w: R += c*M*w also R += c*(-dQ/da)*w Not needed (ex. 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) | |
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 Member Functions inherited from chrono::ChObj | |
ChObj (const ChObj &other) | |
virtual ChObj * | Clone () const =0 |
"Virtual" copy constructor. More... | |
int | GetIdentifier () const |
Gets the numerical identifier of the object. | |
void | SetIdentifier (int id) |
Sets the numerical identifier of the object. | |
double | GetChTime () const |
Gets the simulation time of this object. | |
void | SetChTime (double m_time) |
Sets the simulation time of this object. | |
const char * | GetName () const |
Gets the name of the object as C Ascii null-terminated string -for reading only! | |
void | SetName (const char myname[]) |
Sets the name of this object, as ascii string. | |
std::string | GetNameString () const |
Gets the name of the object as C Ascii null-terminated string. | |
void | SetNameString (const std::string &myname) |
Sets the name of this object, as std::string. | |
void | MFlagsSetAllOFF (int &mflag) |
void | MFlagsSetAllON (int &mflag) |
void | MFlagSetON (int &mflag, int mask) |
void | MFlagSetOFF (int &mflag, int mask) |
int | MFlagGet (int &mflag, int mask) |
virtual void | ArchiveOUT (ChArchiveOut &marchive) |
Method to allow serialization of transient data to archives. | |
virtual void | ArchiveIN (ChArchiveIn &marchive) |
Method to allow de-serialization of transient data from archives. | |
virtual std::string & | ArchiveContainerName () |
Protected Attributes | |
ChLoadJacobians * | jacobians |
Protected Attributes inherited from chrono::ChObj | |
double | ChTime |
the time of simulation for the object | |
Member Function Documentation
◆ ComputeJacobian()
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pure virtual |
Compute the K=-dQ/dx, R=-dQ/dv , M=-dQ/da jacobians.
If possible, override this with an analytical jacobian. Note the sign that is flipped because assuming Q a right hand side, and dQ/d... at left hand side! Called automatically at each Update().
- Parameters
-
state_x state position to evaluate jacobians state_w state speed to evaluate jacobians mK result -dQ/dx mR result -dQ/dv mM result -dQ/da
Implemented in chrono::ChLoadCustomMultiple, chrono::ChLoadCustom, chrono::ChLoadBodyInertia, chrono::ChLoad< Tloader >, chrono::ChLoad< ChLoaderBeamWrench >, chrono::ChLoad< ChLoaderXYZnode >, chrono::ChLoad< ChLoaderBeamWrenchDistributed >, chrono::fea::ChLoadContactSurfaceMesh, and chrono::ChLoadBodyMesh.
◆ ComputeQ()
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pure virtual |
Compute Q, the generalized load(s).
Where Q is stored depends on children classes. Called automatically at each Update().
- Parameters
-
state_x state position to evaluate Q state_w state speed to evaluate Q
Implemented in chrono::fea::ChLoadXYZROTnodeBody, chrono::ChLoadXYZnodeBody, chrono::ChLoadBodyBody, chrono::ChLoadBodyInertia, chrono::ChLoadXYZnodeXYZnode, chrono::ChShaftsElasticGear, chrono::ChLoad< Tloader >, chrono::ChLoad< ChLoaderBeamWrench >, chrono::ChLoad< ChLoaderXYZnode >, chrono::ChLoad< ChLoaderBeamWrenchDistributed >, chrono::fea::ChLoadXYZROTnodeXYZROTnode, chrono::ChLoadBodyTorque, chrono::ChLoadXYZnodeForce, chrono::fea::ChLoadContactSurfaceMesh, chrono::ChLoadBodyForce, chrono::ChLoadBodyMesh, chrono::fea::ChLoadXYZROTnode, and chrono::ChShaftsLoad.
◆ IsStiff()
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pure virtual |
Report if this is load is stiff.
If so, InjectKRMmatrices will provide the jacobians of the load.
Implemented in chrono::fea::ChLoadXYZROTnodeBodyBushingGeneric, chrono::ChLoadBodyBodyBushingGeneric, chrono::fea::ChLoadXYZROTnodeBodyBushingSpherical, chrono::ChLoadXYZnodeBodyBushing, chrono::ChLoadXYZnodeBodySpring, chrono::ChLoadBodyBodyBushingSpherical, chrono::fea::ChLoadXYZROTnodeXYZROTnodeBushingGeneric, chrono::ChLoadXYZnodeXYZnodeBushing, chrono::ChLoadXYZnodeXYZnodeSpring, chrono::fea::ChLoadXYZROTnodeXYZROTnodeBushingSpherical, chrono::ChLoadXYZnodeXYZnode, chrono::ChLoad< Tloader >, chrono::ChLoad< ChLoaderBeamWrench >, chrono::ChLoad< ChLoaderXYZnode >, chrono::ChLoad< ChLoaderBeamWrenchDistributed >, chrono::ChShaftsElasticGear, chrono::ChLoadXYZnodeForceAbsolute, chrono::fea::ChLoadXYZROTnodeForceAbsolute, chrono::ChLoadXYZnodeForce, chrono::fea::ChLoadContactSurfaceMesh, chrono::ChShaftsTorsionSpringDamper, chrono::ChLoadBodyMesh, and chrono::fea::ChLoadXYZROTnode.
◆ KRMmatricesLoad()
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virtual |
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 added with scaling values Kfactor, Rfactor, Mfactor.
Reimplemented in chrono::fea::ChLoadContactSurfaceMesh, and chrono::ChLoadBodyMesh.
◆ LoadIntLoadResidual_Mv()
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pure virtual |
Increment a vector R with a term that has M multiplied a given vector w: R += c*M*w also R += c*(-dQ/da)*w Not needed (ex.
override to {} ) if no M is involved, ex. no inertial effects.
- Parameters
-
R result: the R residual, R += c*M*v w the w vector c scaling factor
Implemented in chrono::ChLoadCustomMultiple, chrono::ChLoadCustom, chrono::ChLoad< Tloader >, chrono::ChLoad< ChLoaderBeamWrench >, chrono::ChLoad< ChLoaderXYZnode >, chrono::ChLoad< ChLoaderBeamWrenchDistributed >, chrono::fea::ChLoadContactSurfaceMesh, chrono::ChLoadBodyMesh, and chrono::ChLoadBodyInertia.
◆ LoadStateIncrement()
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pure 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.
Implemented in chrono::ChLoadCustomMultiple, chrono::ChLoadCustom, chrono::ChLoad< Tloader >, chrono::ChLoad< ChLoaderBeamWrench >, chrono::ChLoad< ChLoaderXYZnode >, chrono::ChLoad< ChLoaderBeamWrenchDistributed >, chrono::fea::ChLoadContactSurfaceMesh, and chrono::ChLoadBodyMesh.
◆ Update()
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virtual |
Update: this is called at least at each time step.
- It recomputes the generalized load Q vector(s)
- It recomputes the jacobian(s) K,R,M in case of stiff load Q and jacobians assumed evaluated at the current state. Jacobian structures are automatically allocated if needed.
Reimplemented in chrono::ChLoadXYZnodeXYZnode, chrono::ChLoadXYZnodeForceAbsolute, chrono::fea::ChLoadXYZROTnodeForceAbsolute, chrono::ChLoadXYZnodeForce, and chrono::fea::ChLoadXYZROTnode.
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono/physics/ChLoad.h
- /builds/uwsbel/chrono/src/chrono/physics/ChLoad.cpp