chrono::modal::ChModalAssembly Class Reference

## 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.

#include <ChModalAssembly.h>

Inheritance diagram for chrono::modal::ChModalAssembly:
Collaboration diagram for chrono::modal::ChModalAssembly:

## Classes

class  CustomForceFullCallback
Class to be used as a callback interface for computing a custom force F applied to the full (not reduced) coordinates; when in reduced mode, this force will be applied with an automatic transformation to the reduced coordinates. More...

class  CustomForceModalCallback
Class to be used as a callback interface for computing a custom force F applied to the modal coordinates. More...

## Public Member Functions

ChModalAssembly (const ChModalAssembly &other)

virtual ChModalAssemblyClone () const override
"Virtual" copy constructor (covariant return type).

ChModalAssemblyoperator= (ChModalAssembly other)
Assignment operator for ChModalAssembly.

void SetModalMode (bool mmodal)
Set true to ignore the dofs of all the "internal" bodies, meshes, etc. More...

bool IsModalMode ()

bool ComputeModes (const ChModalSolveUndamped &n_modes_settings)
Compute the undamped modes for the current assembly. More...

bool ComputeModesExternalData (ChSparseMatrix &mM, ChSparseMatrix &mK, ChSparseMatrix &full_Cq, const ChModalSolveUndamped &n_modes_settings)
Compute the undamped modes from M and K matrices. Later you can fetch results via Get_modes_V() etc. More...

bool ComputeModesDamped (const ChModalSolveDamped &n_modes_settings)
Compute the damped modes for the entire assembly. More...

void SwitchModalReductionON (const ChModalSolveUndamped &n_modes_settings, const ChModalDamping &damping_model=ChModalDampingNone())
Perform modal reduction on this assembly, from the current "full" ("boundary"+"internal") assembly. More...

void SwitchModalReductionON (ChSparseMatrix &full_M, ChSparseMatrix &full_K, ChSparseMatrix &full_Cq, const ChModalSolveUndamped &n_modes_settings, const ChModalDamping &damping_model=ChModalDampingNone())
Perform modal reduction on this 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...

void SetFullStateWithModeOverlay (int n_mode, double phase, double amplitude)
For displaying modes, you can use the following function. More...

void SetInternalStateWithModes (bool full_update)
For displaying the deformation using internal nodes, you can use the following function. More...

void SetFullStateReset ()
Resets the state of this subassembly (both boundary and inner items) to the state snapshot that was taken when doing the last ComputeModes() or ComputeModesDamped().

void GetStateLocal (ChStateDelta &Dx_local, ChStateDelta &v_local)
Computes the 'local' increment of the subassembly (increment of configuration respect to the x0 snapshot configuration, in local reference), and also gets the speed in local reference.

void SetInternalNodesUpdate (bool mflag)
Optimization flag. More...

int Get_n_modes_coords_w ()
Get the number of modal coordinates. Use SwitchModalReductionOn() to change it.

ChVectorDynamicGet_modal_q ()
Access the vector of modal coordinates.

ChVectorDynamicGet_modal_q_dt ()
Access the vector of time derivative of modal coordinates (speeds)

ChVectorDynamicGet_modal_q_dtdt ()
Access the vector of 2nd time derivative of modal coordinates (accelerations)

void RegisterCallback_CustomForceModal (std::shared_ptr< CustomForceModalCallback > mcallback)
Specify the optional callback object for computing a custom modal force.

void RegisterCallback_CustomForceFull (std::shared_ptr< CustomForceFullCallback > mcallback)
Specify the optional callback object for computing a custom force acting on the full (not reduced) coordinates.

ChVectorDynamicGet_custom_F_modal ()
Access the current value of vector of custom applied forces to modal coordinates. More...

ChVectorDynamicGet_custom_F_full ()
Access the current value of vector of custom applied forces to original coordinates. More...

const ChMatrixDynamicGet_modal_M () const
Access the modal mass matrix - read only.

const ChMatrixDynamicGet_modal_K () const
Access the modal stiffness matrix - read only.

const ChMatrixDynamicGet_modal_R () const
Access the modal damping matrix - read only.

const ChMatrixDynamicGet_modal_Psi () const
Access the Psi matrix as in v_full = Psi * v_reduced, also {v_boundary; v_internal} = Psi * {v_boundary; v_modes} Hence Psi contains the "static modes" and the selected "dynamic modes", as in Psi = [I, 0; Psi_s, Psi_d] where Psi_d is the matrix of the selected eigenvectors after SwitchModalReductionON().

const ChVectorDynamicGet_assembly_x0 () const
Access the snapshot of initial state of the full assembly just at the beginning of SwitchModalReductionON()

const ChMatrixDynamic< std::complex< double > > & Get_modes_V () const
Access the modal eigenvectors, if previously computed. More...

const ChVectorDynamic< std::complex< double > > & Get_modes_eig () const
Access the modal eigenvalues, if previously computed. More...

const ChVectorDynamic< double > & Get_modes_frequencies () const
Get a vector of (undamped) modal natural frequencies [Hz], if previously computed. More...

const ChVectorDynamic< double > & Get_modes_damping_ratios () const
Get a vector of modal damping ratios = damping/critical_damping, if previously computed. More...

const ChVectorDynamicGet_modes_assembly_x0 () const
Access the snapshot of initial state of the assembly at the moment of the analysis. More...

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 assembly.

Attach an internal link to this assembly.

void AddInternalMesh (std::shared_ptr< fea::ChMesh > mesh)
Attach an internal mesh to this 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 assembly.

Remove an internal link from this assembly.

void RemoveInternalMesh (std::shared_ptr< fea::ChMesh > mesh)
Remove an internal mesh from the 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 added to the assembly.

void RemoveAllInternalBodies ()
Remove all internal bodies from this assembly.

Remove all internal links from this assembly.

void RemoveAllInternalMeshes ()
Remove all meshes from this assembly.

void RemoveAllInternalOtherPhysicsItems ()
Remove all physics items not in the body, link, or mesh lists.

const std::vector< std::shared_ptr< ChBody > > & Get_internal_bodylist () const
Get the list of internal bodies.

Get the list of internal links.

const std::vector< std::shared_ptr< fea::ChMesh > > & Get_internal_meshlist () const
Get the list of internal meshes.

const std::vector< std::shared_ptr< ChPhysicsItem > > & Get_internal_otherphysicslist () const
Get the list of internal physics items that are not in the body or link lists.

int GetN_internal_bodies () const
Get the number of internal bodies.

Get the number of internal links.

int GetN_internal_meshes () const
Get the number of internal meshes.

int GetN_internal_physicsItems () const
Get the number of other internal physics items (other than bodies, links, or meshes).

int GetN_internal_coords () const
Get the number of internal coordinates (considering 7 coords for rigid bodies because of the 4 dof of quaternions).

int GetN_internal_dof () const
Get the number of internal degrees of freedom of the assembly.

int GetN_internal_doc () const
Get the number of internal scalar constraints added to the assembly, including constraints on quaternion norms because of the 4 dof of quaternions.

int GetN_internal_sysvars () const
Get the number of internal system variables (coordinates plus the constraint multipliers, in case of quaternions).

int GetN_internal_coords_w () const
Get the number of internal coordinates (considering 6 coords for rigid bodies, 3 transl.+3rot.)

int GetN_internal_doc_w () const
Get the number of internal scalar constraints added to the assembly.

int GetN_internal_doc_w_C () const
Get the number of internal scalar constraints added to the assembly (only bilaterals).

int GetN_internal_doc_w_D () const
Get the number of internal scalar constraints added to the assembly (only unilaterals).

int GetN_internal_sysvars_w () const
Get the number of internal system variables (coordinates plus the constraint multipliers).

int GetN_boundary_bodies () const
Get the number of boundary bodies.

Get the number of boundary links.

int GetN_boundary_meshes () const
Get the number of boundary meshes.

int GetN_boundary_physicsItems () const
Get the number of other boundary physics items (other than bodies, links, or meshes).

int GetN_boundary_coords () const
Get the number of boundary coordinates (considering 7 coords for rigid bodies because of the 4 dof of quaternions).

int GetN_boundary_dof () const
Get the number of boundary degrees of freedom of the assembly.

int GetN_boundary_doc () const
Get the number of boundary scalar constraints added to the assembly, including constraints on quaternion norms because of the 4 dof of quaternions.

int GetN_boundary_sysvars () const
Get the number of boundary system variables (coordinates plus the constraint multipliers, in case of quaternions).

int GetN_boundary_coords_w () const
Get the number of boundary coordinates (considering 6 coords for rigid bodies, 3 transl.+3rot.)

int GetN_boundary_doc_w () const
Get the number of boundary scalar constraints added to the assembly.

int GetN_boundary_doc_w_C () const
Get the number of boundary scalar constraints added to the assembly (only bilaterals).

int GetN_boundary_doc_w_D () const
Get the number of boundary scalar constraints added to the assembly (only unilaterals).

int GetN_boundary_sysvars_w () const
Get the number of boundary system variables (coordinates plus the constraint multipliers).

void DumpSubassemblyMatrices (bool save_M, bool save_K, bool save_R, bool save_Cq, const char *path)
Dump the M mass matrix, K damping matrix, R damping matrix, Cq constraint jacobian matrix (at the current configuration) for this subassembly, Assumes the rows/columns of the matrices are ordered as the ChVariable objects used in this assembly, first the all the "boundary" variables then all the "inner" variables (or modal variables if switched to modal assembly). More...

void GetSubassemblyMassMatrix (ChSparseMatrix *M)
Compute the mass matrix of the subassembly. More...

void GetSubassemblyStiffnessMatrix (ChSparseMatrix *K)
Compute the stiffness matrix of the subassembly, i.e. More...

void GetSubassemblyDampingMatrix (ChSparseMatrix *R)
Compute the stiffness matrix of the subassembly, i.e. More...

void GetSubassemblyConstraintJacobianMatrix (ChSparseMatrix *Cq)
Compute the constraint jacobian matrix of the subassembly, i.e. 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
If this physical item contains one or more collision models, synchronize their coordinates and bounding boxes to the state of the item.

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 SetNoSpeedNoAcceleration () override
Set zero speed (and zero accelerations) in state, without changing the position.

virtual int GetDOF () override
Get the number of scalar coordinates (ex. dim of position vector)

virtual int GetDOF_w () override
Get the number of scalar coordinates of variables derivatives (ex. dim of speed vector)

virtual int GetDOC () override
Get the number of scalar constraints, if any, in this item.

virtual int GetDOC_c () override
Get the number of scalar constraints, if any, in this item (only bilateral constr.)

virtual int GetDOC_d () 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 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 &mdescriptor) override
Tell to a system descriptor that there are variables of type ChVariables in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

virtual void InjectConstraints (ChSystemDescriptor &mdescriptor) override
Tell to a system descriptor that there are constraints of type ChConstraint in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

Adds the current jacobians in encapsulated ChConstraints.

virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor) override
Tell to a system descriptor that there are items of type ChKblock in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

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 ArchiveOUT (ChArchiveOut &marchive) override
Method to allow serialization of transient data to archives.

virtual void ArchiveIN (ChArchiveIn &marchive) override
Method to allow deserialization of transient data from archives.

Public Member Functions inherited from chrono::ChAssembly
ChAssembly (const ChAssembly &other)

ChAssemblyoperator= (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.

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.

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.

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.

const std::vector< std::shared_ptr< ChBody > > & Get_bodylist () const
Get the list of bodies.

const std::vector< std::shared_ptr< ChShaft > > & Get_shaftlist () const
Get the list of shafts.

const std::vector< std::shared_ptr< fea::ChMesh > > & Get_meshlist () const
Get the list of meshes.

const std::vector< std::shared_ptr< ChPhysicsItem > > & Get_otherphysicslist () const
Get the list of physics items that are not in the body or link lists.

std::shared_ptr< ChBodySearchBody (const char *name)
Search a body by its name.

std::shared_ptr< ChBodySearchBodyID (int bodyID)
Search a body by its ID.

std::shared_ptr< ChShaftSearchShaft (const char *name)
Search a shaft by its name.

Search a link by its name.

std::shared_ptr< fea::ChMeshSearchMesh (const char *name)
Search a mesh by its name.

std::shared_ptr< ChPhysicsItemSearchOtherPhysicsItem (const char *name)
Search from other ChPhysics items (not bodies, links, or meshes) by name.

std::shared_ptr< ChMarkerSearchMarker (const char *name)
Search a marker by its name.

std::shared_ptr< ChMarkerSearchMarker (int markID)
Search a marker by its unique ID.

std::shared_ptr< ChPhysicsItemSearch (const char *name)
Search an item (body, link or other ChPhysics items) by name.

int GetNbodies () const
Get the number of active bodies (so, excluding those that are sleeping or are fixed to ground).

int GetNbodiesSleeping () const
Get the number of bodies that are in sleeping mode (excluding fixed bodies).

int GetNbodiesFixed () const
Get the number of bodies that are fixed to ground.

int GetNbodiesTotal () const
Get the total number of bodies added to the assembly, including the grounded and sleeping bodies.

int GetNshafts () const
Get the number of shafts.

int GetNshaftsSleeping () const
Get the number of shafts that are in sleeping mode (excluding fixed shafts).

int GetNshaftsFixed () const
Get the number of shafts that are fixed to ground.

int GetNshaftsTotal () const
Get the total number of shafts added to the assembly, including the grounded and sleeping shafts.

int GetNmeshes () const
Get the number of meshes.

int GetNphysicsItems () const
Get the number of other physics items (other than bodies, links, or meshes).

int GetNcoords () const
Get the number of coordinates (considering 7 coords for rigid bodies because of the 4 dof of quaternions).

int GetNdof () const
Get the number of degrees of freedom of the assembly.

int GetNdoc () const
Get the number of scalar constraints added to the assembly, including constraints on quaternion norms.

int GetNsysvars () const
Get the number of system variables (coordinates plus the constraint multipliers, in case of quaternions).

int GetNcoords_w () const
Get the number of coordinates (considering 6 coords for rigid bodies, 3 transl.+3rot.)

int GetNdoc_w () const
Get the number of scalar constraints added to the assembly.

int GetNdoc_w_C () const
Get the number of scalar constraints added to the assembly (only bilaterals).

int GetNdoc_w_D () const
Get the number of scalar constraints added to the assembly (only unilaterals).

int GetNsysvars_w () const
Get the number of system variables (coordinates plus the constraint multipliers).

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.

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 (ChStreamOutAscii &m_file, int level=0) const
Writes the hierarchy of contained bodies, markers, etc. More...

Public Member Functions inherited from chrono::ChPhysicsItem
ChPhysicsItem (const ChPhysicsItem &other)

ChSystemGetSystem () const
Get the pointer to the parent ChSystem().

void AddVisualModel (std::shared_ptr< ChVisualModel > model)
Add an (optional) visualization model. More...

std::shared_ptr< ChVisualModelGetVisualModel () 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< ChVisualShapeGetVisualShape (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< ChVisualShapeFEAGetVisualShapeFEA (unsigned int i) const
Access the specified FEA visualization object in the visualization model (if any). More...

virtual ChFrame GetVisualModelFrame (unsigned int nclone=0)
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 GetCollide () const
Tell if the object is subject to collision. More...

If this physical item contains one or more collision models, add them to the system's collision engine.

virtual void RemoveCollisionModelsFromSystem ()
If this physical item contains one or more collision models, remove them from the system's collision engine.

virtual void GetTotalAABB (ChVector<> &bbmin, ChVector<> &bbmax)
Get the entire AABB axis-aligned bounding box of the object. More...

virtual void GetCenter (ChVector<> &mcenter)
Get a symbolic 'center' of the object. More...

virtual void StreamINstate (ChStreamInBinary &mstream)
Method to deserialize only the state (position, speed) Must be implemented by child classes.

virtual void StreamOUTstate (ChStreamOutBinary &mstream)
Method to serialize only the state (position, speed) Must be implemented by child classes.

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
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 std::string & ArchiveContainerName ()

## Protected Member Functions

void SetupModalData (int nmodes_reduction)
Resize modal matrices and hook up the variables to the M K R block for the solver. More...

## Friends

class ChSystem

class ChSystemMulticore

class ChSystemDistributed

void swap (ChModalAssembly &first, ChModalAssembly &second)
Swap the contents of the two provided ChAssembly objects. More...

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< 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

int nbodies
number of bodies (currently active)

int nbodies_sleep
number of bodies that are sleeping

int nbodies_fixed
number of bodies that are fixed

int nshafts
number of shafts (currently active)

int nshafts_sleep
number of shafts that are sleeping

int nshafts_fixed
number of shafts that are fixed

int nmeshes
number of meshes

int nphysicsitems
number of other physics items

int ncoords
number of scalar coordinates (including 4th dimension of quaternions) for all active bodies

int ndoc
number of scalar constraints (including constr. on quaternions)

int nsysvars
number of variables (coords+lagrangian mult.), i.e. = ncoords+ndoc for all active bodies

int ncoords_w
number of scalar coordinates when using 3 rot. dof. per body; for all active bodies

int ndoc_w
number of scalar constraints when using 3 rot. dof. per body; for all active bodies

int nsysvars_w
number of variables when using 3 rot. dof. per body; i.e. = ncoords_w+ndoc_w

int ndof
number of degrees of freedom, = ncoords-ndoc = ncoords_w-ndoc_w ,

int ndoc_w_C
number of scalar constraints C, when using 3 rot. dof. per body (excluding unilaterals)

int ndoc_w_D
number of scalar constraints D, when using 3 rot. dof. per body (only unilaterals)

Protected Attributes inherited from chrono::ChPhysicsItem
ChSystemsystem
parent system

std::shared_ptr< ChVisualModelInstancevis_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
the time of simulation for the object

## Member Function Documentation

 void chrono::modal::ChModalAssembly::AddInternal ( std::shared_ptr< ChPhysicsItem > item )

Attach an arbitrary internal ChPhysicsItem (e.g.

ChBody, ChParticles, ChLink, etc.) to the assembly. It will take care of adding it to the proper list of internal bodies, links, meshes, or generic physic item.

## ◆ ComputeModes()

 bool chrono::modal::ChModalAssembly::ComputeModes ( const ChModalSolveUndamped & n_modes_settings )

Compute the undamped modes for the current assembly.

Later you can fetch results via Get_modes_V(), Get_modes_frequencies() etc. Usually done for the assembly in full mode, but can be done also SwitchModalReductionON() int as n. of lower modes to keep, or a full ChModalSolveUndamped

## ◆ ComputeModesDamped()

 bool chrono::modal::ChModalAssembly::ComputeModesDamped ( const ChModalSolveDamped & n_modes_settings )

Compute the damped modes for the entire assembly.

Expect complex eigenvalues/eigenvectors if damping is used. Later you can fetch results via Get_modes_V(), Get_modes_frequencies(), Get_modes_damping_ratios() etc. Usually done for the assembly in full mode, but can be done also after SwitchModalReductionON() int as the n. of lower modes to keep, or a full ChModalSolveDamped

## ◆ ComputeModesExternalData()

 bool chrono::modal::ChModalAssembly::ComputeModesExternalData ( ChSparseMatrix & mM, ChSparseMatrix & mK, ChSparseMatrix & full_Cq, const ChModalSolveUndamped & n_modes_settings )

Compute the undamped modes from M and K matrices. Later you can fetch results via Get_modes_V() etc.

int as the n. of lower modes to keep, or a full ChModalSolveUndamped

## ◆ DumpSubassemblyMatrices()

 void chrono::modal::ChModalAssembly::DumpSubassemblyMatrices ( bool save_M, bool save_K, bool save_R, bool save_Cq, const char * path )

Dump the M mass matrix, K damping matrix, R damping matrix, Cq constraint jacobian matrix (at the current configuration) for this subassembly, Assumes the rows/columns of the matrices are ordered as the ChVariable objects used in this assembly, first the all the "boundary" variables then all the "inner" variables (or modal variables if switched to modal assembly).

The name of the files will be [path]_M.dat [path]_K.dat [path]_R.dat [path]_Cq.dat Might throw ChException if file can't be saved.

## ◆ Get_custom_F_full()

 ChVectorDynamic& chrono::modal::ChModalAssembly::Get_custom_F_full ( )
inline

Access the current value of vector of custom applied forces to original coordinates.

Use a CustomForceFullCallback to change it.

## ◆ Get_custom_F_modal()

 ChVectorDynamic& chrono::modal::ChModalAssembly::Get_custom_F_modal ( )
inline

Access the current value of vector of custom applied forces to modal coordinates.

Use a CustomForceModalCallback to change it.

## ◆ Get_modes_assembly_x0()

 const ChVectorDynamic& chrono::modal::ChModalAssembly::Get_modes_assembly_x0 ( ) const
inline

Access the snapshot of initial state of the assembly at the moment of the analysis.

Read only. Use one of the ComputeModes() functions to set it.

## ◆ Get_modes_damping_ratios()

 const ChVectorDynamic& chrono::modal::ChModalAssembly::Get_modes_damping_ratios ( ) const
inline

Get a vector of modal damping ratios = damping/critical_damping, if previously computed.

Read only. Use one of the ComputeModes() functions to set it.

## ◆ Get_modes_eig()

 const ChVectorDynamic >& chrono::modal::ChModalAssembly::Get_modes_eig ( ) const
inline

Access the modal eigenvalues, if previously computed.

Read only. Use one of the ComputeModes() functions to set it.

## ◆ Get_modes_frequencies()

 const ChVectorDynamic& chrono::modal::ChModalAssembly::Get_modes_frequencies ( ) const
inline

Get a vector of (undamped) modal natural frequencies [Hz], if previously computed.

Read only. Use one of the ComputeModes() functions to set it.

## ◆ Get_modes_V()

 const ChMatrixDynamic >& chrono::modal::ChModalAssembly::Get_modes_V ( ) const
inline

Access the modal eigenvectors, if previously computed.

Read only. Use one of the ComputeModes() functions to set it.

## ◆ GetSubassemblyConstraintJacobianMatrix()

 void chrono::modal::ChModalAssembly::GetSubassemblyConstraintJacobianMatrix ( ChSparseMatrix * Cq )

Compute the constraint jacobian matrix of the subassembly, i.e.

the jacobian Cq=-dC/dq where C are constraints (the lower left part of the KKT matrix). Assumes the columns of the matrix are ordered as the ChVariable objects used in this assembly, i.e. first the all the "boundary" variables then all the "inner" variables (or modal variables if switched to modal assembly), and assumes the rows of the matrix are ordered as the constraints used in this assembly, i.e. first the boundary and then the inner. fill this system damping matrix

## ◆ GetSubassemblyDampingMatrix()

 void chrono::modal::ChModalAssembly::GetSubassemblyDampingMatrix ( ChSparseMatrix * R )

Compute the stiffness matrix of the subassembly, i.e.

the jacobian -dF/dv where F are stiff loads. Assumes the rows/columns of the matrix are ordered as the ChVariable objects used in this assembly, first the all the "boundary" variables then all the "inner" variables (or modal variables if switched to modal assembly). Note that not all loads provide a jacobian, as this is optional in their implementation. fill this system damping matrix

## ◆ GetSubassemblyMassMatrix()

 void chrono::modal::ChModalAssembly::GetSubassemblyMassMatrix ( ChSparseMatrix * M )

Compute the mass matrix of the subassembly.

Assumes the rows/columns of the matrix are ordered as the ChVariable objects used in this assembly, first the all the "boundary" itvariablesems then all the "inner" variables (or modal variables if switched to modal assembly). fill this system mass matrix

## ◆ GetSubassemblyStiffnessMatrix()

 void chrono::modal::ChModalAssembly::GetSubassemblyStiffnessMatrix ( ChSparseMatrix * K )

Compute the stiffness matrix of the subassembly, i.e.

the jacobian -dF/dq where F are stiff loads. Assumes the rows/columns of the matrix are ordered as the ChVariable objects used in this assembly, first the all the "boundary" variables then all the "inner" variables (or modal variables if switched to modal assembly). Note that not all loads provide a jacobian, as this is optional in their implementation. fill this system stiffness matrix

## ◆ IntFromDescriptor()

 void chrono::modal::ChModalAssembly::IntFromDescriptor ( const unsigned int off_v, ChStateDelta & v, const unsigned int off_L, ChVectorDynamic<> & L )
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.

 void chrono::modal::ChModalAssembly::IntLoadConstraint_C ( const unsigned int off, ChVectorDynamic<> & Qc, const double c, bool do_clamp, double recovery_clamp )
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.

 void chrono::modal::ChModalAssembly::IntLoadConstraint_Ct ( const unsigned int off, ChVectorDynamic<> & Qc, const double c )
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.

 void chrono::modal::ChModalAssembly::IntLoadResidual_CqL ( const unsigned int off_L, ChVectorDynamic<> & R, const ChVectorDynamic<> & L, const double c )
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.

 void chrono::modal::ChModalAssembly::IntLoadResidual_F ( const unsigned int off, ChVectorDynamic<> & R, const double c )
overridevirtual

Takes the F force term, scale and adds to R at given offset: R += c*F.

Parameters
 off offset in R residual R result: the R residual, R += c*F c a scaling factor

Reimplemented from chrono::ChAssembly.

 void chrono::modal::ChModalAssembly::IntLoadResidual_Mv ( const unsigned int off, ChVectorDynamic<> & R, const ChVectorDynamic<> & w, const double c )
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()

 void chrono::modal::ChModalAssembly::IntStateGather ( const unsigned int off_x, ChState & x, const unsigned int off_v, ChStateDelta & v, double & T )
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()

 void chrono::modal::ChModalAssembly::IntStateGatherAcceleration ( const unsigned int off_a, ChStateDelta & a )
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()

 void chrono::modal::ChModalAssembly::IntStateGatherReactions ( const unsigned int off_L, ChVectorDynamic<> & L )
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()

 void chrono::modal::ChModalAssembly::IntStateGetIncrement ( const unsigned int off_x, const ChState & x_new, const ChState & x, const unsigned int off_v, ChStateDelta & Dv )
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()

 void chrono::modal::ChModalAssembly::IntStateIncrement ( const unsigned int off_x, ChState & x_new, const ChState & x, const unsigned int off_v, const ChStateDelta & Dv )
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()

 void chrono::modal::ChModalAssembly::IntStateScatter ( const unsigned int off_x, const ChState & x, const unsigned int off_v, const ChStateDelta & v, const double T, bool full_update )
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()

 void chrono::modal::ChModalAssembly::IntStateScatterAcceleration ( const unsigned int off_a, const ChStateDelta & a )
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()

 void chrono::modal::ChModalAssembly::IntStateScatterReactions ( const unsigned int off_L, const ChVectorDynamic<> & L )
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()

 void chrono::modal::ChModalAssembly::IntToDescriptor ( const unsigned int off_v, const ChStateDelta & v, const ChVectorDynamic<> & R, const unsigned int off_L, const ChVectorDynamic<> & L, const ChVectorDynamic<> & Qc )
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.

 void chrono::modal::ChModalAssembly::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 added with scaling values Kfactor, Rfactor, Mfactor. NOTE: signs are flipped respect to the ChTimestepper dF/dx terms: K = -dF/dq, R = -dF/dv

Reimplemented from chrono::ChAssembly.

## ◆ SetFullStateWithModeOverlay()

 void chrono::modal::ChModalAssembly::SetFullStateWithModeOverlay ( int n_mode, double phase, double amplitude )

For displaying modes, you can use the following function.

It sets the state of this subassembly (both boundary and inner items) using the n-th eigenvector multiplied by a "amplitude" factor * sin(phase). If you increment the phase during an animation, you will see the n-ht mode oscillating on the screen. It works also if in IsModalMode(). The mode shape is added to the state snapshot that was taken when doing the last ComputeModes() or ComputeModesDamped().

## ◆ SetInternalNodesUpdate()

 void chrono::modal::ChModalAssembly::SetInternalNodesUpdate ( bool mflag )

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 reasons. In sake of high CPU performance, if no interest in visualization/postprocessing, one can disable this setting to false.

## ◆ SetInternalStateWithModes()

 void chrono::modal::ChModalAssembly::SetInternalStateWithModes ( bool full_update )

For displaying the deformation using internal nodes, you can use the following function.

Works only if IsModalMode(). It sets the state of the internal nodes of this subassembly using the current state of the modal coordinates q given the computed eigenvalues: x=V*q , then it overlays s to the state snapshot x0 stored last time one called a modal analysis. This is not necessary, but useful during animations, in fact the internal nodes would be completely neglected if IsModalMode() ; but calling this function one can update their changing positions for visualization, stress recovery, etc.

## ◆ SetModalMode()

 void chrono::modal::ChModalAssembly::SetModalMode ( bool mmodal )
inline

Set true to ignore the dofs of all the "internal" bodies, meshes, etc.

(those added with AddInternal() ) and just use the "boundary" bodies, meshes, etc. (those normally added via Add() ). Set false to consider all internal bodies, meshes etc. as normal items in a normal assembly.

## ◆ Setup()

 void chrono::modal::ChModalAssembly::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.

## ◆ SetupModalData()

 void chrono::modal::ChModalAssembly::SetupModalData ( int nmodes_reduction )
protected

Resize modal matrices and hook up the variables to the M K R block for the solver.

To be used all times the n. of modes of modal reduction (n_modes_coords_w) is changed.

## ◆ SwitchModalReductionON() [1/2]

 void chrono::modal::ChModalAssembly::SwitchModalReductionON ( ChSparseMatrix & full_M, ChSparseMatrix & full_K, ChSparseMatrix & full_Cq, const ChModalSolveUndamped & n_modes_settings, const ChModalDamping & damping_model = ChModalDampingNone() )

Perform modal reduction on this 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.

• with an external FEA software, the full assembly is modeled with "boundary"+"internal" nodes.
• with an external FEA software, the M mass matrix and the K stiffness matrix are saved to disk.
• in Chrono, M and K and Cq constraint jacobians (if any) are load from disk and stored in ChSparseMatrix objects
• in Chrono, only boundary nodes are added to a ChModalAssembly
• in Chrono, run this function passing such M and K matrices: a modal analysis will be done on K and M Note that the size of M (and K) must be at least > n_boundary_coords_w.
a damping model to use for the reduced model
Parameters
 n_modes_settings int as the n. of lower modes to keep, or a full ChModalSolveUndamped

## ◆ SwitchModalReductionON() [2/2]

 void chrono::modal::ChModalAssembly::SwitchModalReductionON ( const ChModalSolveUndamped & n_modes_settings, const ChModalDamping & damping_model = ChModalDampingNone() )

Perform modal reduction on this assembly, from the current "full" ("boundary"+"internal") assembly.

• An undamped modal analysis will be done on the full assembly with nodes.
• The "internal" nodes will be replaced by n_modes modal coordinates. a damping model to use for the reduced model
Parameters
 n_modes_settings int as the n. of lower modes to keep, or a full ChModalSolveUndamped

## ◆ swap

 void swap ( ChModalAssembly & first, ChModalAssembly & second )
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