Description
Class for assemblies of items, for example ChBody, ChLink, ChMesh, etc.
This supports component mode synthesis (CMS) to do substructuring, hence an assembly becomes a "modal body" where many "internal" DOFs of finite elements will be reduced to few modal modes that are superimposed to the motion of a floating frame (for small deflections). Some nodes can be selected as "boundary nodes" to allow connecting this modal assembly to external joints and forces.
The development of this modal reduction procedure has been inspired by the research paper: Sonneville, V., Scapolan, M., Shan, M. et al. Modal reduction procedures for flexible multibody dynamics. Multibody Syst Dyn 51, 377–418 (2021).
#include <ChModalAssembly.h>
Public Types | |
enum | ReductionType { ReductionType::HERTING, ReductionType::CRAIG_BAMPTON } |
Modal reduction methods. More... | |
Public Member Functions | |
ChModalAssembly (const ChModalAssembly &other) | |
virtual ChModalAssembly * | Clone () const override |
"Virtual" copy constructor (covariant return type). | |
ChModalAssembly & | operator= (ChModalAssembly other) |
Assignment operator for ChModalAssembly. | |
void | SetReductionType (ReductionType type) |
Set the type of modal reduction to be used. | |
ReductionType | GetReductionType () const |
Get the type of modal reduction used. | |
template<typename EigensolverType > | |
void | DoModalReduction (const ChModalSolverUndamped< EigensolverType > &modal_solver, const ChModalDamping &damping_model=ChModalDampingNone()) |
Perform modal reduction on this modal assembly, from the current "full" ("boundary"+"internal") assembly. More... | |
template<typename EigensolverType > | |
void | DoModalReduction (ChSparseMatrix &full_M, ChSparseMatrix &full_K, ChSparseMatrix &full_Cq, const ChModalSolverUndamped< EigensolverType > &modal_solver, const ChModalDamping &damping_model=ChModalDampingNone()) |
Perform modal reduction on this modal assembly that contains only the "boundary" nodes, whereas the "internal" nodes have been modeled only in an external FEA software with the full ("boundary"+"internal") modes. More... | |
ChFrameMoving | GetFloatingFrameOfReference () |
Get the floating frame F of the reduced modal assembly. | |
const ChVectorDynamic & | GetConstraintsResidualF () |
Get the residual of constraint equations on the floating frame F. More... | |
void | SetVerbose (bool verbose) |
Set verbose output. | |
void | SetUseStaticCorrection (bool flag) |
Set whether the static correction is used. More... | |
bool | GetUsetStaticCorrection () |
Get the flag whether the static correction is used. | |
void | SetUseLinearInertialTerm (bool flag) |
A rigorous mathematical manipulation can be employed to derive the inertial forces and the consequent inertial damping matrix, or a linear assumption is applied to obtain quite concise expressions. More... | |
void | UpdateInternalState (bool full_update) |
(both boundary and internal items) using the n-th eigenvector multiplied by an "amplitude" factor * sin(phase). More... | |
void | SetFullStateReset () |
Resets the state of this modal assembly (both boundary and internal items) to the state snapshot in the initial configuration. | |
void | SetInternalNodesUpdate (bool flag) |
Optimization flag. More... | |
void | SetModalAutomaticGravity (bool gravity) |
If true, as by default, this modal assembly will add automatically a gravity load to all contained boundary and internal bodies/nodes (that support gravity) in the modal reduced state using the G value from the ChSystem. More... | |
bool | GetModalAutomaticGravity () |
Tell if this modal assembly will add automatically a gravity load to all contained boundary and internal bodies/nodes. | |
const ChMatrixDynamic & | GetModalMassMatrix () const |
Get the modal mass matrix. | |
const ChMatrixDynamic & | GetModalStiffnessMatrix () const |
Get the modal stiffness matrix. | |
const ChMatrixDynamic & | GetModalDampingMatrix () const |
Get the modal damping matrix. | |
const ChMatrixDynamic & | GetModalReductionMatrix () const |
Get the modal reduction transformation matrix 'Psi'. More... | |
const ChMatrixDynamic< std::complex< double > > & | GetEigenVectors () const |
Get the modal eigenvectors, if previously computed. More... | |
const ChVectorDynamic< std::complex< double > > & | GetEigenValues () const |
Get the modal eigenvalues, if previously computed. More... | |
const ChVectorDynamic< double > & | GetUndampedFrequencies () const |
Get a vector of (undamped) modal natural frequencies [Hz], if previously computed. More... | |
const ChVectorDynamic< double > & | GetDampingRatios () const |
Get a vector of modal damping ratios = damping/critical_damping, if previously computed. More... | |
const ChVectorDynamic & | GetDeformedState () const |
Get the deformed configuration of the full modal assembly. | |
const ChVectorDynamic & | GetInitialState () const |
Get the initial full state of the modal assembly before the modal reduction. | |
ChVectorDynamic & | GetModalCoordinatesPosLevel () |
Get the vector of modal coordinates (positions). | |
ChVectorDynamic & | GetModalCoordinatesVelLevel () |
Get the vector of time derivative of modal coordinates (velocities). | |
ChVectorDynamic & | GetModalCoordinatesAccLevel () |
Get the vector of 2nd time derivative of modal coordinates (accelerations). | |
void | Clear () |
Removes all inserted items: bodies, links, etc., both boundary and internal. | |
void | AddInternalBody (std::shared_ptr< ChBody > body) |
Attach an internal body to this modal assembly. | |
void | AddInternalLink (std::shared_ptr< ChLinkBase > link) |
Attach an internal link to this modal assembly. More... | |
void | AddInternalMesh (std::shared_ptr< fea::ChMesh > mesh) |
Attach an internal mesh to this modal assembly. | |
void | AddInternalOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item) |
Attach an internal ChPhysicsItem object that is not a body, link, or mesh. | |
void | AddInternal (std::shared_ptr< ChPhysicsItem > item) |
Attach an arbitrary internal ChPhysicsItem (e.g. More... | |
void | RemoveInternalBody (std::shared_ptr< ChBody > body) |
Remove an internal body from this modal assembly. | |
void | RemoveInternalLink (std::shared_ptr< ChLinkBase > link) |
Remove an internal link from this modal assembly. | |
void | RemoveInternalMesh (std::shared_ptr< fea::ChMesh > mesh) |
Remove an internal mesh from this modal assembly. | |
void | RemoveInternalOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item) |
Remove an internal ChPhysicsItem object that is not a body or a link. | |
void | RemoveInternal (std::shared_ptr< ChPhysicsItem > item) |
Remove an internal arbitrary ChPhysicsItem that was. | |
void | RemoveAllInternalBodies () |
Remove all internal bodies from this modal assembly. | |
void | RemoveAllInternalLinks () |
Remove all internal links from this modal assembly. | |
void | RemoveAllInternalMeshes () |
Remove all meshes from this modal assembly. | |
void | RemoveAllInternalOtherPhysicsItems () |
Remove all physics items not in the body, link, or mesh lists. | |
virtual const std::vector< std::shared_ptr< ChBody > > & | GetBodies () const override |
Get the list of both boundary and internal bodies. | |
virtual const std::vector< std::shared_ptr< ChLinkBase > > & | GetLinks () const override |
Get the list of both boundary and internal links. | |
virtual const std::vector< std::shared_ptr< fea::ChMesh > > & | GetMeshes () const override |
Get the list of both boundary and internal meshes. | |
virtual const std::vector< std::shared_ptr< ChPhysicsItem > > & | GetOtherPhysicsItems () const override |
Get the list of both boundary and internal physics items that are not in the body or link lists. | |
const std::vector< std::shared_ptr< ChBody > > & | GetBodiesInternal () const |
Get the list of internal bodies. | |
const std::vector< std::shared_ptr< ChLinkBase > > & | GetLinksInternal () const |
Get the list of internal links. | |
const std::vector< std::shared_ptr< fea::ChMesh > > & | GetMeshesInternal () const |
Get the list of internal meshes. | |
const std::vector< std::shared_ptr< ChPhysicsItem > > & | GetOtherPhysicsItemsInternal () const |
Get the list of internal physics items that are not in the body or link lists. | |
unsigned int | GetNumBodiesInternal () const |
Get the number of internal bodies. | |
unsigned int | GetNumLinksInternal () const |
Get the number of internal links. | |
unsigned int | GetNumMeshesInternal () const |
Get the number of internal meshes. | |
unsigned int | GetNumOtherPhysicsItemsInternal () const |
Get the number of other internal physics items (other than bodies, links, or meshes). | |
unsigned int | GetNumCoordinatesPosInternal () const |
Get the number of internal coordinates at the position level. More... | |
unsigned int | GetNumCoordinatesVelInternal () const |
Get the number of internal coordinates at the velocity level. More... | |
unsigned int | GetNumConstraintsInternal () const |
Get the number of internal scalar constraints. | |
unsigned int | GetNumConstraintsBilateralInternal () const |
Get the number of internal bilateral scalar constraints. | |
unsigned int | GetNumConstraintsUnilateralInternal () const |
Get the number of internal unilateral scalar constraints. | |
unsigned int | GetNumBodiesBoundary () const |
Get the number of boundary bodies. | |
unsigned int | GetNumLinksBoundary () const |
Get the number of boundary links. | |
unsigned int | GetNumMeshesBoundary () const |
Get the number of boundary meshes. | |
unsigned int | GetNumOtherPhysicsItemsBoundary () const |
Get the number of other boundary physics items (other than bodies, links, or meshes). | |
unsigned int | GetNumCoordinatesPosBoundary () const |
Get the number of boundary coordinates at the position level. More... | |
unsigned int | GetNumCoordinatesVelBoundary () const |
Get the number of boundary coordinates at the velocity level. More... | |
unsigned int | GetNumConstraintsBoundary () const |
Get the number of boundary scalar constraints. | |
unsigned int | GetNumConstraintsBilateralBoundary () const |
Get the number of boundary scalar bilateral constraints (only bilaterals). | |
unsigned int | GetNumConstraintsUnilateralBoundary () const |
Get the number of boundary scalar constraints (only unilaterals). | |
int | GetNumCoordinatesModal () |
Get the number of modal coordinates. Use DoModalReduction() to change it. | |
void | WriteSubassemblyMatrices (bool save_M, bool save_K, bool save_R, bool save_Cq, const std::string &path, bool one_indexed=true) |
Write the mass (M), damping (K), damping (R), and constraint Jacobian (C) matrices at current configuration. More... | |
void | GetSubassemblyMatrices (ChSparseMatrix *K, ChSparseMatrix *R, ChSparseMatrix *M, ChSparseMatrix *Cq) |
Retrieves the stiffness, damping, mass and constraint Jacobian matrices of the modal assembly. More... | |
virtual void | SetSystem (ChSystem *m_system) override |
Set the pointer to the parent ChSystem() and also add to new collision system / remove from old coll.system. | |
virtual void | SyncCollisionModels () override |
Synchronize collision models for all physics items in this assembly. | |
virtual void | Setup () override |
Counts the number of bodies, links, and meshes. More... | |
virtual void | Update (bool update_assets=true) override |
Updates all the auxiliary data and children of bodies, forces, links, given their current state. | |
virtual void | ForceToRest () override |
Set zero speed (and zero accelerations) in state, without changing the position. | |
virtual unsigned int | GetNumCoordsPosLevel () override |
Get the number of scalar coordinates (ex. dim of position vector) | |
virtual unsigned int | GetNumCoordsVelLevel () override |
Get the number of scalar coordinates of variables derivatives (ex. dim of speed vector) | |
virtual unsigned int | GetNumConstraints () override |
Get the number of scalar constraints, if any, in this item. | |
virtual unsigned int | GetNumConstraintsBilateral () override |
Get the number of scalar constraints, if any, in this item (only bilateral constr.) | |
virtual unsigned int | GetNumConstraintsUnilateral () override |
Get the number of scalar constraints, if any, in this item (only unilateral constr.) | |
virtual void | IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T) override |
From item's state to global state vectors y={x,v} pasting the states at the specified offsets. More... | |
virtual void | IntStateScatter (const unsigned int off_x, const ChState &x, const unsigned int off_v, const ChStateDelta &v, const double T, bool full_update) override |
From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets. More... | |
virtual void | IntStateGatherAcceleration (const unsigned int off_a, ChStateDelta &a) override |
From item's state acceleration to global acceleration vector. More... | |
virtual void | IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override |
From global acceleration vector to item's state acceleration. More... | |
virtual void | IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override |
From item's reaction forces to global reaction vector. More... | |
virtual void | IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override |
From global reaction vector to item's reaction forces. More... | |
virtual void | IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override |
Computes x_new = x + Dt , using vectors at specified offsets. More... | |
virtual void | IntStateGetIncrement (const unsigned int off_x, const ChState &x_new, const ChState &x, const unsigned int off_v, ChStateDelta &Dv) override |
Computes Dt = x_new - x, using vectors at specified offsets. More... | |
virtual void | IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c) override |
Takes the F force term, scale and adds to R at given offset: R += c*F. More... | |
virtual void | IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override |
Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w. More... | |
virtual void | IntLoadLumpedMass_Md (const unsigned int off, ChVectorDynamic<> &Md, double &err, const double c) override |
Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More... | |
virtual void | IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override |
Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L. More... | |
virtual void | IntLoadConstraint_C (const unsigned int off, ChVectorDynamic<> &Qc, const double c, bool do_clamp, double recovery_clamp) override |
Takes the term C, scale and adds to Qc at given offset: Qc += c*C. More... | |
virtual void | IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c) override |
Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More... | |
virtual void | IntToDescriptor (const unsigned int off_v, const ChStateDelta &v, const ChVectorDynamic<> &R, const unsigned int off_L, const ChVectorDynamic<> &L, const ChVectorDynamic<> &Qc) override |
Prepare variables and constraints to accommodate a solution: More... | |
virtual void | IntFromDescriptor (const unsigned int off_v, ChStateDelta &v, const unsigned int off_L, ChVectorDynamic<> &L) override |
After a solver solution, fetch values from variables and constraints into vectors: More... | |
virtual void | InjectVariables (ChSystemDescriptor &descriptor) override |
Register with the given system descriptor any ChVariable objects associated with this item. | |
virtual void | InjectConstraints (ChSystemDescriptor &descriptor) override |
Register with the given system descriptor any ChConstraint objects associated with this item. | |
virtual void | LoadConstraintJacobians () override |
Compute and load current Jacobians in encapsulated ChConstraint objects. | |
virtual void | InjectKRMMatrices (ChSystemDescriptor &descriptor) override |
Register with the given system descriptor any ChKRMBlock objects associated with this item. | |
virtual void | LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override |
Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More... | |
double | GetTimeMatrixAssembly () const |
Get cumulative time for matrix assembly. | |
double | GetTimeSetup () const |
Get cumulative time for setup. | |
double | GetTimeModalSolver () const |
Get cumulative time for modal solver. | |
void | ResetTimers () |
Reset all timers. | |
virtual void | ArchiveOut (ChArchiveOut &archive_out) override |
Method to allow serialization of transient data to archives. | |
virtual void | ArchiveIn (ChArchiveIn &archive_in) override |
Method to allow deserialization of transient data from archives. | |
Public Member Functions inherited from chrono::ChAssembly | |
ChAssembly (const ChAssembly &other) | |
ChAssembly & | operator= (ChAssembly other) |
Assignment operator for ChAssembly. | |
void | Clear () |
Removes all inserted items: bodies, links, etc. | |
void | AddBody (std::shared_ptr< ChBody > body) |
Attach a body to this assembly. | |
void | AddShaft (std::shared_ptr< ChShaft > shaft) |
Attach a shaft to this assembly. | |
void | AddLink (std::shared_ptr< ChLinkBase > link) |
Attach a link to this assembly. | |
void | AddMesh (std::shared_ptr< fea::ChMesh > mesh) |
Attach a mesh to this assembly. | |
void | AddOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item) |
Attach a ChPhysicsItem object that is not a body, link, or mesh. | |
void | Add (std::shared_ptr< ChPhysicsItem > item) |
Attach an arbitrary ChPhysicsItem (e.g. More... | |
void | AddBatch (std::shared_ptr< ChPhysicsItem > item) |
Items added in this way are added like in the Add() method, but not instantly, they are simply queued in a batch of 'to add' items, that are added automatically at the first Setup() call. More... | |
void | FlushBatch () |
If some items are queued for addition in the assembly, using AddBatch(), this will effectively add them and clean the batch. More... | |
void | RemoveBody (std::shared_ptr< ChBody > body) |
Remove a body from this assembly. | |
void | RemoveShaft (std::shared_ptr< ChShaft > shaft) |
Remove a shaft from this assembly. | |
void | RemoveLink (std::shared_ptr< ChLinkBase > link) |
Remove a link from this assembly. | |
void | RemoveMesh (std::shared_ptr< fea::ChMesh > mesh) |
Remove a mesh from the assembly. | |
void | RemoveOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item) |
Remove a ChPhysicsItem object that is not a body or a link. | |
void | Remove (std::shared_ptr< ChPhysicsItem > item) |
Remove arbitrary ChPhysicsItem that was added to the assembly. | |
void | RemoveAllBodies () |
Remove all bodies from this assembly. | |
void | RemoveAllShafts () |
Remove all shafts from this assembly. | |
void | RemoveAllLinks () |
Remove all links from this assembly. | |
void | RemoveAllMeshes () |
Remove all meshes from this assembly. | |
void | RemoveAllOtherPhysicsItems () |
Remove all physics items not in the body, link, or mesh lists. | |
virtual const std::vector< std::shared_ptr< ChShaft > > & | GetShafts () const |
Get the list of shafts. | |
std::shared_ptr< ChBody > | SearchBody (const std::string &name) const |
Search a body by its name. | |
std::shared_ptr< ChBody > | SearchBodyID (int id) const |
Search a body by its ID. | |
std::shared_ptr< ChShaft > | SearchShaft (const std::string &name) const |
Search a shaft by its name. | |
std::shared_ptr< ChLinkBase > | SearchLink (const std::string &name) const |
Search a link by its name. | |
std::shared_ptr< fea::ChMesh > | SearchMesh (const std::string &name) const |
Search a mesh by its name. | |
std::shared_ptr< ChPhysicsItem > | SearchOtherPhysicsItem (const std::string &name) const |
Search from other ChPhysics items (not bodies, links, or meshes) by name. | |
std::shared_ptr< ChMarker > | SearchMarker (const std::string &name) const |
Search a marker by its name. | |
std::shared_ptr< ChMarker > | SearchMarker (int id) const |
Search a marker by its unique ID. | |
std::shared_ptr< ChPhysicsItem > | Search (const std::string &name) const |
Search an item (body, link or other ChPhysics items) by name. | |
unsigned int | GetNumBodies () const |
Get the total number of bodies added to the assembly, including fixed and sleeping bodies. | |
unsigned int | GetNumBodiesActive () const |
Get the number of active bodies, excluding sleeping or fixed. | |
unsigned int | GetNumBodiesSleeping () const |
Get the number of sleeping bodies. | |
unsigned int | GetNumBodiesFixed () const |
Get the number of bodies fixed to ground. | |
unsigned int | GetNumShafts () const |
Get the number of shafts. | |
unsigned int | GetNumShaftsSleeping () const |
Get the number of shafts that are in sleeping mode (excluding fixed shafts). | |
unsigned int | GetNumShaftsFixed () const |
Get the number of shafts that are fixed to ground. | |
unsigned int | GetNumShaftsTotal () const |
Get the total number of shafts added to the assembly, including the grounded and sleeping shafts. | |
unsigned int | GetNumLinks () const |
Get the number of links (including non active). | |
unsigned int | GetNumLinksActive () const |
Get the number of active links. | |
unsigned int | GetNumMeshes () const |
Get the number of meshes. | |
unsigned int | GetNumOtherPhysicsItems () const |
Get the number of other active physics items (including non active). | |
unsigned int | GetNumOtherPhysicsItemsActive () const |
Get the number of other active physics items. | |
virtual void | AddCollisionModelsToSystem (ChCollisionSystem *coll_sys) const override |
Add collision models (if any) for all items in the assembly to the provided collision system. | |
virtual void | RemoveCollisionModelsFromSystem (ChCollisionSystem *coll_sys) const override |
Remove the collision models (if any) for all items in the assembly from the provided collision system. | |
virtual void | Update (double mytime, bool update_assets=true) override |
Updates all the auxiliary data and children of bodies, forces, links, given their current state. | |
virtual void | VariablesFbReset () override |
Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero. | |
virtual void | VariablesFbLoadForces (double factor=1) override |
Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor. | |
virtual void | VariablesQbLoadSpeed () override |
Initialize the 'qb' part of the ChVariables with the current value of speeds. More... | |
virtual void | VariablesFbIncrementMq () override |
Adds M*q (masses multiplied current 'qb') to Fb, ex. More... | |
virtual void | VariablesQbSetSpeed (double step=0) override |
Fetches the item speed (ex. More... | |
virtual void | VariablesQbIncrementPosition (double step) override |
Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More... | |
virtual void | ConstraintsBiReset () override |
Sets to zero the known term (b_i) of encapsulated ChConstraints. | |
virtual void | ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false) override |
Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints. | |
virtual void | ConstraintsBiLoad_Ct (double factor=1) override |
Adds the current Ct (partial t-derivative, as in C_dt=0-> [Cq]*q_dt=-Ct) to the known term (b_i) of encapsulated ChConstraints. | |
virtual void | ConstraintsBiLoad_Qc (double factor=1) override |
Adds the current Qc (the vector of C_dtdt=0 -> [Cq]*q_dtdt=Qc ) to the known term (b_i) of encapsulated ChConstraints. | |
virtual void | ConstraintsFbLoadForces (double factor=1) override |
Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints. | |
virtual void | ConstraintsFetch_react (double factor=1) override |
Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More... | |
void | ShowHierarchy (std::ostream &outstream, int level=0) const |
Writes the hierarchy of contained bodies, markers, etc. More... | |
Public Member Functions inherited from chrono::ChPhysicsItem | |
ChPhysicsItem (const ChPhysicsItem &other) | |
ChSystem * | GetSystem () const |
Get the pointer to the parent ChSystem(). | |
void | AddVisualModel (std::shared_ptr< ChVisualModel > model) |
Add an (optional) visualization model. More... | |
std::shared_ptr< ChVisualModel > | GetVisualModel () const |
Access the visualization model (if any). More... | |
void | AddVisualShape (std::shared_ptr< ChVisualShape > shape, const ChFrame<> &frame=ChFrame<>()) |
Add the specified visual shape to the visualization model. More... | |
std::shared_ptr< ChVisualShape > | GetVisualShape (unsigned int i) const |
Access the specified visualization shape in the visualization model (if any). More... | |
void | AddVisualShapeFEA (std::shared_ptr< ChVisualShapeFEA > shapeFEA) |
Add the specified FEA visualization object to the visualization model. More... | |
std::shared_ptr< ChVisualShapeFEA > | GetVisualShapeFEA (unsigned int i) const |
Access the specified FEA visualization object in the visualization model (if any). More... | |
virtual ChFrame | GetVisualModelFrame (unsigned int nclone=0) const |
Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More... | |
virtual unsigned int | GetNumVisualModelClones () const |
Return the number of clones of the visual model associated with this physics item. More... | |
void | AddCamera (std::shared_ptr< ChCamera > camera) |
Attach a ChCamera to this physical item. More... | |
std::vector< std::shared_ptr< ChCamera > > | GetCameras () const |
Get the set of cameras attached to this physics item. | |
virtual bool | IsActive () const |
Return true if the object is active and included in dynamics. | |
virtual bool | IsCollisionEnabled () const |
Tell if the object is subject to collision. More... | |
virtual ChAABB | GetTotalAABB () const |
Get the axis-aligned bounding box (AABB) of this object. More... | |
virtual ChVector3d | GetCenter () const |
Get a symbolic 'center' of the object. More... | |
void | UpdateVisualModel () |
Utility function to update only the associated visual assets (if any). | |
unsigned int | GetOffset_x () |
Get offset in the state vector (position part) | |
unsigned int | GetOffset_w () |
Get offset in the state vector (speed part) | |
unsigned int | GetOffset_L () |
Get offset in the lagrangian multipliers. | |
void | SetOffset_x (const unsigned int moff) |
Set offset in the state vector (position part) Note: only the ChSystem::Setup function should use this. | |
void | SetOffset_w (const unsigned int moff) |
Set offset in the state vector (speed part) Note: only the ChSystem::Setup function should use this. | |
void | SetOffset_L (const unsigned int moff) |
Set offset in the lagrangian multipliers Note: only the ChSystem::Setup function should use this. | |
Public Member Functions inherited from chrono::ChObj | |
ChObj (const ChObj &other) | |
int | GetIdentifier () const |
Get the unique integer identifier of this object. More... | |
void | SetTag (int tag) |
Set an object integer tag (default: -1). More... | |
int | GetTag () const |
Get the tag of this object. | |
void | SetName (const std::string &myname) |
Set the name of this object. | |
const std::string & | GetName () const |
Get the name of this object. | |
double | GetChTime () const |
Gets the simulation time of this object. | |
void | SetChTime (double m_time) |
Sets the simulation time of this object. | |
virtual std::string & | ArchiveContainerName () |
Friends | |
class | ChSystem |
class | ChSystemMulticore |
void | swap (ChModalAssembly &first, ChModalAssembly &second) |
Swap the contents of the two provided ChAssembly objects. More... | |
Additional Inherited Members | |
Protected Member Functions inherited from chrono::ChObj | |
int | GenerateUniqueIdentifier () |
Protected Attributes inherited from chrono::ChAssembly | |
std::vector< std::shared_ptr< ChBody > > | bodylist |
list of rigid bodies | |
std::vector< std::shared_ptr< ChShaft > > | shaftlist |
list of 1-D shafts | |
std::vector< std::shared_ptr< ChLinkBase > > | linklist |
list of joints (links) | |
std::vector< std::shared_ptr< fea::ChMesh > > | meshlist |
list of meshes | |
std::vector< std::shared_ptr< ChPhysicsItem > > | otherphysicslist |
list of other physics objects | |
std::vector< std::shared_ptr< ChPhysicsItem > > | batch_to_insert |
list of items to insert at once | |
unsigned int | m_num_bodies_active |
number of active bodies | |
unsigned int | m_num_bodies_sleep |
number of sleeping bodies | |
unsigned int | m_num_bodies_fixed |
number of fixed bodies | |
unsigned int | m_num_shafts |
number of active shafts | |
unsigned int | m_num_shafts_sleep |
number of sleeping shafts | |
unsigned int | m_num_shafts_fixed |
number of fixed shafts | |
unsigned int | m_num_links_active |
number of active links | |
unsigned int | m_num_meshes |
number of meshes | |
unsigned int | m_num_otherphysicsitems_active |
number of other active physics items | |
unsigned int | m_num_coords_pos |
number of scalar position-level coordinates for all active bodies | |
unsigned int | m_num_coords_vel |
number of scalar velocity-level coordinates for all active bodies | |
unsigned int | m_num_constr |
number of scalar constraints | |
unsigned int | m_num_constr_bil |
number of scalar bilateral constraints | |
unsigned int | m_num_constr_uni |
number of scalar unilateral constraints | |
Protected Attributes inherited from chrono::ChPhysicsItem | |
ChSystem * | system |
parent system | |
std::shared_ptr< ChVisualModelInstance > | vis_model_instance |
instantiated visualization model | |
std::vector< std::shared_ptr< ChCamera > > | cameras |
set of cameras | |
unsigned int | offset_x |
offset in vector of state (position part) | |
unsigned int | offset_w |
offset in vector of state (speed part) | |
unsigned int | offset_L |
offset in vector of lagrangian multipliers | |
Protected Attributes inherited from chrono::ChObj | |
double | ChTime |
object simulation time | |
std::string | m_name |
object name | |
int | m_identifier |
object unique identifier | |
int | m_tag |
user-supplied tag | |
Member Enumeration Documentation
◆ ReductionType
|
strong |
Constructor & Destructor Documentation
◆ ChModalAssembly()
chrono::modal::ChModalAssembly::ChModalAssembly | ( | const ChModalAssembly & | other | ) |
TODO: deep copy of the object lists (internal_bodylist, internal_linklist, internal_meshlist, internal_otherphysicslist)
Member Function Documentation
◆ AddInternal()
void chrono::modal::ChModalAssembly::AddInternal | ( | std::shared_ptr< ChPhysicsItem > | item | ) |
Attach an arbitrary internal ChPhysicsItem (e.g.
ChBody, ChParticles, ChLink, etc.) to the modal assembly. It will take care of adding it to the proper list of internal bodies, links, meshes, or generic physic item.
◆ AddInternalLink()
void chrono::modal::ChModalAssembly::AddInternalLink | ( | std::shared_ptr< ChLinkBase > | link | ) |
Attach an internal link to this modal assembly.
- AddInternalLink(): to link "boundary nodes" with "internal nodes", or "internal nodes" with "internal nodes", which will be reduced;
- AddLink(): to link "boundary nodes" with "boundary nodes", which will be computed and updated in the full state.
◆ GetConstraintsResidualF()
|
inline |
Get the residual of constraint equations on the floating frame F.
The configuration of the floating frame F is determined by the six constraint equations using a Newton-Raphson iteration. The residual of constraint equations is an indicator to check the convergence of the modal method.
◆ GetDampingRatios()
|
inline |
Get a vector of modal damping ratios = damping/critical_damping, if previously computed.
Use one of the ComputeModes() functions to set it.
◆ GetEigenValues()
|
inline |
Get the modal eigenvalues, if previously computed.
These are the eigenvalues of the original assembly with applied boundary conditions, depending on reduction type. Use one of the ComputeModes() functions to set it.
◆ GetEigenVectors()
|
inline |
Get the modal eigenvectors, if previously computed.
These are the eigenvectors of the original assembly with applied boundary conditions, depending on reduction type. Use one of the ComputeModes() functions to set it.
◆ GetModalReductionMatrix()
|
inline |
Get the modal reduction transformation matrix 'Psi'.
'Psi' as in v_full = Psi * v_reduced, also {v_boundary; v_internal} = Psi * {v_boundary; v_modes}. Hence Psi contains the "static modes", the selected "dynamic modes" and the "static correction mode", as Psi = [ I 0 0 ] [ Psi_S Psi_D Psi_Cor ] [ Psi_S_LambdaI Psi_D_LambdaI Psi_Cor_LambdaI ] where Psi_D is the matrix of the selected eigenvectors after DoModalReduction(), Psi_Cor is the static correction mode which depends on the external forces imposed on the internal bodies and nodes.
◆ GetNumCoordinatesPosBoundary()
|
inline |
Get the number of boundary coordinates at the position level.
Might differ from GetNumCoordinatesPosInternal in case of quaternions.
◆ GetNumCoordinatesPosInternal()
|
inline |
Get the number of internal coordinates at the position level.
Might differ from GetNumCoordinatesPosInternal in case of quaternions.
◆ GetNumCoordinatesVelBoundary()
|
inline |
Get the number of boundary coordinates at the velocity level.
Might differ from GetNumCoordinatesPosInternal in case of quaternions.
◆ GetNumCoordinatesVelInternal()
|
inline |
Get the number of internal coordinates at the velocity level.
Might differ from GetNumCoordinatesPosInternal in case of quaternions.
◆ GetSubassemblyMatrices()
void chrono::modal::ChModalAssembly::GetSubassemblyMatrices | ( | ChSparseMatrix * | K, |
ChSparseMatrix * | R, | ||
ChSparseMatrix * | M, | ||
ChSparseMatrix * | Cq | ||
) |
Retrieves the stiffness, damping, mass and constraint Jacobian matrices of the modal assembly.
All the matrices are consistent with the ordering of objects in the modal assembly; first the "boundary" variables, followed by either the internal variables (if in full state) or the modal variables (if in modal reduced state). Please not that not all loads provide a "stiffness" jacobian, as this is optional in their implementation i.e. -dF/dq is not available in the stiffness matrix for such objects
◆ GetUndampedFrequencies()
|
inline |
Get a vector of (undamped) modal natural frequencies [Hz], if previously computed.
These are the frequencies of the original assembly with applied boundary conditions, depending on reduction type. Use one of the ComputeModes() functions to set it.
◆ IntFromDescriptor()
|
overridevirtual |
After a solver solution, fetch values from variables and constraints into vectors:
- Parameters
-
off_v offset for v v vector to where the q 'unknowns' term of the variables will be copied off_L offset for L L vector to where L 'lagrangian ' term of the constraints will be copied
Reimplemented from chrono::ChAssembly.
◆ IntLoadConstraint_C()
|
overridevirtual |
Takes the term C, scale and adds to Qc at given offset: Qc += c*C.
- Parameters
-
off offset in Qc residual Qc result: the Qc residual, Qc += c*C c a scaling factor do_clamp apply clamping to c*C? recovery_clamp value for min/max clamping of c*C
Reimplemented from chrono::ChAssembly.
◆ IntLoadConstraint_Ct()
|
overridevirtual |
Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct.
- Parameters
-
off offset in Qc residual Qc result: the Qc residual, Qc += c*Ct c a scaling factor
Reimplemented from chrono::ChAssembly.
◆ IntLoadLumpedMass_Md()
|
overridevirtual |
Adds the lumped mass to a Md vector, representing a mass diagonal matrix.
Used by lumped explicit integrators. If mass lumping is impossible or approximate, adds scalar error to "error" parameter. Md += c*diag(M)
- Parameters
-
off offset in Md vector Md result: Md vector, diagonal of the lumped mass matrix err result: not touched if lumping does not introduce errors c a scaling factor
Reimplemented from chrono::ChAssembly.
◆ IntLoadResidual_CqL()
|
overridevirtual |
Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L.
- Parameters
-
off_L offset in L multipliers R result: the R residual, R += c*Cq'*L L the L vector c a scaling factor
Reimplemented from chrono::ChAssembly.
◆ IntLoadResidual_F()
|
overridevirtual |
Takes the F force term, scale and adds to R at given offset: R += c*F.
g_quadvel: the quadratic velocity term of the reduced modal superelement
- Parameters
-
off offset in R residual R result: the R residual, R += c*F c a scaling factor
Reimplemented from chrono::ChAssembly.
◆ IntLoadResidual_Mv()
|
overridevirtual |
Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w.
- Parameters
-
off offset in R residual R result: the R residual, R += c*M*v w the w vector c a scaling factor
Reimplemented from chrono::ChAssembly.
◆ IntStateGather()
|
overridevirtual |
From item's state to global state vectors y={x,v} pasting the states at the specified offsets.
- Parameters
-
off_x offset in x state vector x state vector, position part off_v offset in v state vector v state vector, speed part T time
Reimplemented from chrono::ChAssembly.
◆ IntStateGatherAcceleration()
|
overridevirtual |
From item's state acceleration to global acceleration vector.
- Parameters
-
off_a offset in a accel. vector a acceleration part of state vector derivative
Reimplemented from chrono::ChAssembly.
◆ IntStateGatherReactions()
|
overridevirtual |
From item's reaction forces to global reaction vector.
- Parameters
-
off_L offset in L vector L L vector of reaction forces
Reimplemented from chrono::ChAssembly.
◆ IntStateGetIncrement()
|
overridevirtual |
Computes Dt = x_new - x, using vectors at specified offsets.
By default, when DOF = DOF_w, it does just the difference of two state vectors, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.
- Parameters
-
off_x offset in x state vector x_new state vector, final position part x state vector, initial position part off_v offset in v state vector Dv state vector, increment. Here gets the result
Reimplemented from chrono::ChAssembly.
◆ IntStateIncrement()
|
overridevirtual |
Computes x_new = x + Dt , using vectors at specified offsets.
By default, when DOF = DOF_w, it does just the sum, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.
- Parameters
-
off_x offset in x state vector x_new state vector, position part, incremented result x state vector, initial position part off_v offset in v state vector Dv state vector, increment
Reimplemented from chrono::ChAssembly.
◆ IntStateScatter()
|
overridevirtual |
From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.
- Parameters
-
off_x offset in x state vector x state vector, position part off_v offset in v state vector v state vector, speed part T time full_update perform complete update
Reimplemented from chrono::ChAssembly.
◆ IntStateScatterAcceleration()
|
overridevirtual |
From global acceleration vector to item's state acceleration.
- Parameters
-
off_a offset in a accel. vector a acceleration part of state vector derivative
Reimplemented from chrono::ChAssembly.
◆ IntStateScatterReactions()
|
overridevirtual |
From global reaction vector to item's reaction forces.
- Parameters
-
off_L offset in L vector L L vector of reaction forces
Reimplemented from chrono::ChAssembly.
◆ IntToDescriptor()
|
overridevirtual |
Prepare variables and constraints to accommodate a solution:
- Parameters
-
off_v offset for v and R v vector copied into the q 'unknowns' term of the variables R vector copied into the F 'force' term of the variables off_L offset for L and Qc L vector copied into the L 'lagrangian ' term of the constraints Qc vector copied into the Qb 'constraint' term of the constraints
Reimplemented from chrono::ChAssembly.
◆ LoadKRMMatrices()
|
overridevirtual |
Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects.
The resulting KRM blocks represent linear combinations of the K, R, and M matrices, with the specified coefficients Kfactor, Rfactor,and Mfactor, respectively. Note: signs are flipped from the term dF/dx in the integrator: K = -dF/dq and R = -dF/dv.
Reimplemented from chrono::ChAssembly.
◆ SetInternalNodesUpdate()
void chrono::modal::ChModalAssembly::SetInternalNodesUpdate | ( | bool | flag | ) |
Optimization flag.
Default true: when in modal reduced mode, during simulations the internal (discarded) nodes are updated anyway by superposition of modal shapes etc., for visualization or postprocessing purposes. In sake of high CPU performance, if no interest in visualization/postprocessing, one can disable this by setting to false, then automatically set m_num_coords_static_correction = 0 to disable the static correction mode.
◆ SetModalAutomaticGravity()
|
inline |
If true, as by default, this modal assembly will add automatically a gravity load to all contained boundary and internal bodies/nodes (that support gravity) in the modal reduced state using the G value from the ChSystem.
- In modal reduced state, this flag will overwrite mesh->SetAutomaticGravity() for both boundary and internal meshes.
- In full state, this flap does NOT affect, and mesh->SetAutomaticGravity() is used for both boundary and internal meshes. It is recommended to use a same boolean value to ensure a consistent setting in both full and reduced state, for example:
- modal_assembly->SetModalAutomaticGravity(USE_GRAVITY);
- mesh_internal->SetAutomaticGravity(USE_GRAVITY);
- mesh_boundary->SetAutomaticGravity(USE_GRAVITY);
◆ Setup()
|
overridevirtual |
Counts the number of bodies, links, and meshes.
Computes the offsets of object states in the global state. Assumes that this->offset_x this->offset_w this->offset_L are already set as starting point for offsetting all the contained sub objects.
Reimplemented from chrono::ChAssembly.
◆ SetUseLinearInertialTerm()
|
inline |
A rigorous mathematical manipulation can be employed to derive the inertial forces and the consequent inertial damping matrix, or a linear assumption is applied to obtain quite concise expressions.
- True: default option, the linear assumption is used.
- False: rigorous deviation is used, only for internal test.
◆ SetUseStaticCorrection()
void chrono::modal::ChModalAssembly::SetUseStaticCorrection | ( | bool | flag | ) |
Set whether the static correction is used.
By default, it is false. When some external forces are imposed on the internal bodies and nodes, the static correction is important to obtain a reasonable accurary of the elastic deformation and internal forces of finite elements, and reaction forces of constriants in the modal assembly. In this case, it is strongly recommended to set true. Note: only available to SetUseStaticCorrection(true) when m_internal_nodes_update = true.
◆ UpdateInternalState()
void chrono::modal::ChModalAssembly::UpdateInternalState | ( | bool | full_update | ) |
(both boundary and internal items) using the n-th eigenvector multiplied by an "amplitude" factor * sin(phase).
Updates the state of internal nodes. Works only if FlagModelAsReduced(). It sets the state of the internal nodes of this modal assembly using the current state of the modal coordinates q given the computed eigenvectors: s = V * q , then it overlays s to the state snapshot x0 stored last time one called a modal reduction. This is not necessary, but useful during animations, in fact the internal nodes would be completely neglected if m_internal_nodes_update == false; but calling this function one can update their changing positions for visualization, stress recovery, etc.
◆ WriteSubassemblyMatrices()
void chrono::modal::ChModalAssembly::WriteSubassemblyMatrices | ( | bool | save_M, |
bool | save_K, | ||
bool | save_R, | ||
bool | save_Cq, | ||
const std::string & | path, | ||
bool | one_indexed = true |
||
) |
Write the mass (M), damping (K), damping (R), and constraint Jacobian (C) matrices at current configuration.
Assumes the rows/columns of the matrices are ordered as the ChVariable objects used in this modal assembly, first all the "boundary" variables then all the "internal" variables (or modal variables if switched to modal reduced state). The sparse matrices are saved in COO format in [path]_M.dat [path]_K.dat [path]_R.dat, and [path]_Cq.dat. By default, uses 1-based indices (as in Matlab).
Friends And Related Function Documentation
◆ swap
|
friend |
Swap the contents of the two provided ChAssembly objects.
Implemented as a friend (as opposed to a member function) so classes with a ChModalAssembly member can use ADL when implementing their own swap.
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono_modal/ChModalAssembly.h
- /builds/uwsbel/chrono/src/chrono_modal/ChModalAssembly.cpp