chrono::fea::ChMesh Class Reference

Description

Class which defines a mesh of finite elements of class ChElementBase, between nodes of class ChNodeFEAbase.

#include <ChMesh.h>

Inheritance diagram for chrono::fea::ChMesh:
Collaboration diagram for chrono::fea::ChMesh:

Public Member Functions

 ChMesh (const ChMesh &other)
 
virtual ChMeshClone () const override
 "Virtual" copy constructor (covariant return type).
 
void AddNode (std::shared_ptr< ChNodeFEAbase > m_node)
 
void AddElement (std::shared_ptr< ChElementBase > m_elem)
 
void ClearNodes ()
 
void ClearElements ()
 
const std::vector
< std::shared_ptr
< ChNodeFEAbase > > & 
GetNodes () const
 Get the array of nodes of this mesh.
 
const std::vector
< std::shared_ptr
< ChElementBase > > & 
GetElements () const
 Get the array of elements of this mesh.
 
virtual std::shared_ptr
< ChNodeBase
GetNode (unsigned int n) override
 Access the N-th node.
 
std::shared_ptr< ChElementBaseGetElement (unsigned int n)
 Access the N-th element.
 
virtual unsigned int GetNnodes () const override
 Get the number of nodes in the mesh.
 
unsigned int GetNelements ()
 Get the number of elements in the mesh.
 
virtual int GetDOF () override
 Get the number of scalar coordinates (variables), if any, in this item. More...
 
virtual int GetDOF_w () override
 Get the number of scalar coordinates of variables derivatives (usually = DOF, but might be different than DOF, ex. More...
 
virtual bool GetCollide () const override
 Override default in ChPhysicsItem.
 
void ResetCounters ()
 Reset counters for internal force and Jacobian evaluations.
 
int GetNumCallsInternalForces ()
 Get cumulative number of calls to internal forces evaluation.
 
int GetNumCallsJacobianLoad ()
 Get cumulative number of calls to load Jacobian information.
 
void ResetTimers ()
 Reset timers for internal force and Jacobian evaluations.
 
double GetTimeInternalForces ()
 Get cumulative time for internal force evaluation.
 
double GetTimeJacobianLoad ()
 Get cumulative time for Jacobian load calls.
 
void AddContactSurface (std::shared_ptr< ChContactSurface > m_surf)
 Add a contact surface.
 
std::shared_ptr< ChContactSurfaceGetContactSurface (unsigned int n)
 Access the N-th contact surface.
 
unsigned int GetNcontactSurfaces ()
 Get number of added contact surfaces.
 
void ClearContactSurfaces ()
 Remove all contact surfaces.
 
void AddMeshSurface (std::shared_ptr< ChMeshSurface > m_surf)
 Add a mesh surface (set of ChLoadableUV items that support area loads such as pressure, etc.)
 
std::shared_ptr< ChMeshSurfaceGetMeshSurface (unsigned int n)
 Access the N-th mesh surface.
 
unsigned int GetNmeshSurfaces ()
 Get number of added mesh surfaces.
 
void ClearMeshSurfaces ()
 Remove all mesh surfaces.
 
void Relax ()
 Set reference position of nodes as current position, for all nodes.
 
void SetNoSpeedNoAcceleration () override
 Set no speed and no accelerations in nodes (but does not change reference positions)
 
virtual void Setup () override
 This recomputes the number of DOFs, constraints, as well as state offsets of contained items.
 
virtual void Update (double m_time, bool update_assets=true) override
 Update time dependent data, for all elements. More...
 
virtual void SyncCollisionModels () override
 If this physical item contains one or more collision models, sinchronize their coordinates and bounding boxes to the state of the item. More...
 
virtual void AddCollisionModelsToSystem () override
 If this physical item contains one or more collision models, add them to the system's collision engine. More...
 
virtual void RemoveCollisionModelsFromSystem () override
 If this physical item contains one or more collision models, remove them from the system's collision engine. More...
 
void SetAutomaticGravity (bool mg, int num_points=1)
 If true, as by default, this mesh will add automatically a gravity load to all contained elements (that support gravity) using the G value from the ChSystem. More...
 
bool GetAutomaticGravity ()
 Tell if this mesh will add automatically a gravity load to all contained elements.
 
void ComputeMassProperties (double &mass, ChVector<> &com, ChMatrix33<> &inertia)
 Get ChMesh mass properties. More...
 
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) 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.
 
virtual void IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override
 From global acceleration vector to item's state acceleration.
 
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 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.
 
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 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 for a solution: From a vector R into the F 'force' term of the variables From a vector Qc into the Qb 'constraint' term of the constraints From a vector v into the q 'unknowns' term of the variables (for warm starting) From a vector L into the L 'lagrangian ' term of the constraints (for warm starting) 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: To a vector v from the q 'unknowns' term of the variables To a vector L from the L 'lagrangian ' term of the constraints. More...
 
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. More...
 
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 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 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. More...
 
- Public Member Functions inherited from chrono::ChIndexedNodes
 ChIndexedNodes (const ChIndexedNodes &other)
 
virtual void ArchiveOUT (ChArchiveOut &marchive) override
 Add a new node to the particle cluster, passing a vector as initial position. More...
 
virtual void ArchiveIN (ChArchiveIn &marchive) override
 Method to allow deserialization of transient data from archives.
 
- Public Member Functions inherited from chrono::ChPhysicsItem
 ChPhysicsItem (const ChPhysicsItem &other)
 
ChSystemGetSystem () const
 Get the pointer to the parent ChSystem()
 
virtual void SetSystem (ChSystem *m_system)
 Set the pointer to the parent ChSystem() and also add to new collision system / remove from old coll.system.
 
void AddAsset (std::shared_ptr< ChAsset > masset)
 Add an optional asset (it can be used to define visualization shapes, es ChSphereShape, or textures, or custom attached properties that the user can define by creating his class inherited from ChAsset)
 
std::vector< std::shared_ptr
< ChAsset > > & 
GetAssets ()
 Access to the list of optional assets.
 
std::shared_ptr< ChAssetGetAssetN (unsigned int num)
 Access the Nth asset in the list of optional assets.
 
virtual ChFrame GetAssetsFrame (unsigned int nclone=0)
 Get the master coordinate system for assets that have some geometric meaning. More...
 
virtual unsigned int GetAssetsFrameNclones ()
 Optionally, a ChPhysicsItem can return multiple asset coordinate systems; this can be helpful if, for example, when a ChPhysicsItem contains 'clones' with the same assets (ex. More...
 
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. More...
 
virtual void StreamOUTstate (ChStreamOutBinary &mstream)
 Method to serialize only the state (position, speed) Must be implemented by child classes. More...
 
virtual void Update (bool update_assets=true)
 As above, but does not require updating of time-dependent data. More...
 
virtual int GetDOC ()
 Get the number of scalar constraints, if any, in this item.
 
virtual int GetDOC_c ()
 Get the number of scalar constraints, if any, in this item (only bilateral constr.) Children classes might override this. More...
 
virtual int GetDOC_d ()
 Get the number of scalar constraints, if any, in this item (only unilateral constr.) Children classes might override this. More...
 
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.
 
virtual void IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L)
 From item's reaction forces to global reaction vector. More...
 
virtual void IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L)
 From global reaction vector to item's reaction forces. More...
 
virtual void IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c)
 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)
 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)
 Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...
 
virtual void InjectConstraints (ChSystemDescriptor &mdescriptor)
 Tell to a system descriptor that there are contraints of type ChConstraint in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this. More...
 
virtual void ConstraintsBiReset ()
 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)
 Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_Ct (double factor=1)
 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)
 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)
 Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints.
 
virtual void ConstraintsLoadJacobians ()
 Adds the current jacobians in encapsulated ChConstraints.
 
virtual void ConstraintsFetch_react (double factor=1)
 Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...
 
- 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)
 

Additional Inherited Members

- Protected Attributes inherited from chrono::ChPhysicsItem
ChSystemsystem
 parent system
 
std::vector< std::shared_ptr
< ChAsset > > 
assets
 set of assets
 
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::fea::ChMesh::AddCollisionModelsToSystem ( )
overridevirtual

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

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::ComputeMassProperties ( double &  mass,
ChVector<> &  com,
ChMatrix33<> &  inertia 
)

Get ChMesh mass properties.

Parameters
massChMesh object mass
comChMesh center of gravity
inertiaChMesh inertia tensor
virtual int chrono::fea::ChMesh::GetDOF ( )
overridevirtual

Get the number of scalar coordinates (variables), if any, in this item.

Children classes must override this.

Reimplemented from chrono::ChPhysicsItem.

virtual int chrono::fea::ChMesh::GetDOF_w ( )
overridevirtual

Get the number of scalar coordinates of variables derivatives (usually = DOF, but might be different than DOF, ex.

DOF=4 for quaternions, but DOF_w = 3 for its Lie algebra, ex angular velocity) Children classes might override this.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::InjectKRMmatrices ( ChSystemDescriptor mdescriptor)
overridevirtual

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.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::InjectVariables ( ChSystemDescriptor mdescriptor)
overridevirtual

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.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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: To a vector v from the q 'unknowns' term of the variables To a vector L from the L 'lagrangian ' term of the constraints.

Parameters
off_voffset in v
off_Loffset in L

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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
offoffset in R residual
Rresult: the R residual, R += c*M*v
wthe w vector
ca scaling factor

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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_xoffset in x state vector
xstate vector, position part
off_voffset in v state vector
vstate vector, speed part
Ttime

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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_xoffset in x state vector
x_newstate vector, position part, incremented result
xstate vector, initial position part
off_voffset in v state vector
Dvstate vector, increment

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::IntStateScatter ( const unsigned int  off_x,
const ChState x,
const unsigned int  off_v,
const ChStateDelta v,
const double  T 
)
overridevirtual

From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.

Parameters
off_xoffset in x state vector
xstate vector, position part
off_voffset in v state vector
vstate vector, speed part
Ttime

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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 for a solution: From a vector R into the F 'force' term of the variables From a vector Qc into the Qb 'constraint' term of the constraints From a vector v into the q 'unknowns' term of the variables (for warm starting) From a vector L into the L 'lagrangian ' term of the constraints (for warm starting)

Parameters
off_voffset in v, R
off_Loffset in L, Qc

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::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.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::RemoveCollisionModelsFromSystem ( )
overridevirtual

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

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::SetAutomaticGravity ( bool  mg,
int  num_points = 1 
)

If true, as by default, this mesh will add automatically a gravity load to all contained elements (that support gravity) using the G value from the ChSystem.

So this saves you from adding many ChLoad<ChLoaderGravity> to all elements.

void chrono::fea::ChMesh::SyncCollisionModels ( )
overridevirtual

If this physical item contains one or more collision models, sinchronize their coordinates and bounding boxes to the state of the item.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::Update ( double  m_time,
bool  update_assets = true 
)
overridevirtual

Update time dependent data, for all elements.

Updates all [A] coord.systems for all (corotational) elements.

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::VariablesFbIncrementMq ( )
overridevirtual

Adds M*q (masses multiplied current 'qb') to Fb, ex.

if qb is initialized with v_old using VariablesQbLoadSpeed, this method can be used in timestepping schemes that do: M*v_new = M*v_old + forces*dt

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::VariablesQbIncrementPosition ( double  step)
overridevirtual

Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor.

pos+=qb*step

If qb is a speed, this behaves like a single step of 1-st order numerical integration (Eulero integration).

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::VariablesQbLoadSpeed ( )
overridevirtual

Initialize the 'qb' part of the ChVariables with the current value of speeds.

Note: since 'qb' is the unknown, this function seems unnecessary, unless used before VariablesFbIncrementMq()

Reimplemented from chrono::ChPhysicsItem.

void chrono::fea::ChMesh::VariablesQbSetSpeed ( double  step = 0)
overridevirtual

Fetches the item speed (ex.

linear and angular vel.in rigid bodies) from the 'qb' part of the ChVariables and sets it as the current item speed. If 'step' is not 0, also should compute the approximate acceleration of the item using backward differences, that is accel=(new_speed-old_speed)/step. Mostly used after the solver provided the solution in ChVariables.

Reimplemented from chrono::ChPhysicsItem.