Description

Class for clusters of point nodes that can simulate a fluid or an elastic/plastic solid with the Smooth Particle Hydrodynamics (SPH) approach, that is with a 'meshless' FEA approach.

#include <ChMatterSPH.h>

Inheritance diagram for chrono::ChMatterSPH:

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Collaboration diagram for chrono::ChMatterSPH:

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Public Member Functions
	ChMatterSPH ()
	Build a cluster of nodes for SPH and meshless FEM. More...

	ChMatterSPH (const ChMatterSPH &other)

virtual ChMatterSPH *	Clone () const override
	"Virtual" copy constructor (covariant return type).

void	SetCollide (bool mcoll)
	Enable/disable the collision for this cluster of particles. More...

virtual bool	GetCollide () const override
	Tell if the object is subject to collision. More...

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

virtual unsigned int	GetNnodes () const override
	Get the number of nodes.

virtual std::shared_ptr< ChNodeBase >	GetNode (unsigned int n) override
	Access the N-th node.

void	ResizeNnodes (int newsize)
	Resize the node cluster. More...

void	AddNode (ChVector< double > initial_state)
	Add a new node to the particle cluster, passing a vector as initial position.

void	SetMaterialSurface (const std::shared_ptr< ChMaterialSurface > &mnewsurf)
	Set the material surface for 'boundary contact'.

std::shared_ptr< ChMaterialSurface > &	GetMaterialSurface ()
	Set the material surface for 'boundary contact'.

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. 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	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 Mv term, multiplying mass by a vector, scale and adds to R at given offset: R += cM*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 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	VariablesFbReset () override
	Sets the 'fb' part of the encapsulated ChVariablesBody to zero.

virtual void	VariablesFbLoadForces (double factor=1) override
	Adds the current forces applied to body (including gyroscopic torque) in encapsulated ChVariablesBody, in the 'fb' part: qf+=forces*factor.

virtual void	VariablesQbLoadSpeed () override
	Initialize the 'qb' part of the ChVariablesBody with the current value of body 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 body speed (both linear and angular) from the 'qb' part of the ChVariablesBody (does not updates the full body&markers state) and sets it as the current body speed. More...

virtual void	VariablesQbIncrementPosition (double step) override
	Increment body position by the 'qb' part of the ChVariablesBody, 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.

void	SetNoSpeedNoAcceleration () override
	Set no speed and no accelerations (but does not change the position)

virtual void	SyncCollisionModels () override
	Synchronize coll.models coordinates and bounding boxes to the positions of the particles.

virtual void	AddCollisionModelsToSystem () override
	If this physical item contains one or more collision models, add them to the system's collision engine.

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

void	UpdateParticleCollisionModels ()

ChContinuumSPH &	GetMaterial ()
	Access the material.

void	FillBox (const ChVector<> size, const double spacing, const double initial_density, const ChCoordsys<> cords=CSYSNORM, const bool do_centeredcube=true, const double kernel_sfactor=2.2, const double randomness=0.0)
	Initialize the fluid as a prismatic region filled with nodes, initially well ordered as a lattice. More...

virtual void	Update (double mytime, bool update_assets=true) override
	Update all auxiliary data of the particles.

virtual void	Update (bool update_assets=true) override
	Update all auxiliary data of the particles.

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 de serialization of transient data from archives.

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

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

ChSystem *	GetSystem () 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< ChAsset >	GetAssetN (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.

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

virtual void	Setup ()
	This might recompute the number of coordinates, DOFs, constraints, in case this might change (ex in ChAssembly), as well as state offsets of contained items (ex in ChMesh)

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

virtual int	GetDOC_d ()
	Get the number of scalar constraints, if any, in this item (only unilateral constr.) Children classes might override this.

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	IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv)
	Computes x_new = x + Dt , using vectors at specified offsets. 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 += cCq'*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 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.

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...

virtual void	InjectKRMmatrices (ChSystemDescriptor &mdescriptor)
	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)
	Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. More...

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

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 ()

Additional Inherited Members
Protected Attributes inherited from chrono::ChPhysicsItem
ChSystem *	system
	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

Constructor & Destructor Documentation

◆ ChMatterSPH()

chrono::ChMatterSPH::ChMatterSPH ( )

Build a cluster of nodes for SPH and meshless FEM.

By default the cluster will contain 0 particles.

Member Function Documentation

◆ ArchiveOUT()

void chrono::ChMatterSPH::ArchiveOUT ( ChArchiveOut & marchive )

overridevirtual

Add a new node to the particle cluster, passing a vector as initial position.

Resize the node cluster. Also clear the state of previously created particles, if any. Number of coordinates of the node cluster Method to allow serialization of transient data to archives.

Reimplemented from chrono::ChIndexedNodes.

◆ FillBox()

void chrono::ChMatterSPH::FillBox	(	const ChVector<>	size,
		const double	spacing,
		const double	initial_density,
		const ChCoordsys<>	cords = `CSYSNORM`,
		const bool	do_centeredcube = `true`,
		const double	kernel_sfactor = `2.2`,
		const double	randomness = `0.0`
	)

Initialize the fluid as a prismatic region filled with nodes, initially well ordered as a lattice.

This is a helper function so that you avoid to create all nodes one by one with many calls to AddNode() .

Parameters

size	x,y,z sizes of the box to fill (better if integer multiples of spacing)
spacing	the spacing between two near nodes
initial_density	density of the material inside the box, for initialization of node's masses
cords	position and rotation of the box
do_centeredcube	if false, array is simply cubic, if true is centered cubes (highest regularity)
kernel_sfactor	the radius of kernel of the particle is 'spacing' multiplied this value
randomness	randomness of the initial distribution lattice, 0...1

◆ GetCollide()

virtual bool chrono::ChMatterSPH::GetCollide ( ) const

inlineoverridevirtual

Tell if the object is subject to collision.

Only for interface; child classes may override this, using internal flags.

Reimplemented from chrono::ChPhysicsItem.

◆ IntFromDescriptor()

void chrono::ChMatterSPH::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::ChPhysicsItem.

◆ IntLoadResidual_F()

void chrono::ChMatterSPH::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::ChPhysicsItem.

◆ IntLoadResidual_Mv()

void chrono::ChMatterSPH::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 += cMv
w	the w vector
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGather()

void chrono::ChMatterSPH::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::ChPhysicsItem.

◆ IntStateGatherAcceleration()

void chrono::ChMatterSPH::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::ChPhysicsItem.

◆ IntStateScatter()

void chrono::ChMatterSPH::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_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::ChPhysicsItem.

◆ IntStateScatterAcceleration()

void chrono::ChMatterSPH::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::ChPhysicsItem.

◆ IntToDescriptor()

void chrono::ChMatterSPH::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 that will be copied into the q 'unknowns' term of the variables (for warm starting)
R	vector that will be copied into the F 'force' term of the variables
off_L	offset for L and Qc
L	vector that will be copied into the L 'lagrangian ' term of the constraints (for warm starting)
Qc	vector that will be copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

◆ ResizeNnodes()

void chrono::ChMatterSPH::ResizeNnodes ( int newsize )

Resize the node cluster.

Also clear the state of previously created particles, if any.

◆ SetCollide()

void chrono::ChMatterSPH::SetCollide ( bool mcoll )

Enable/disable the collision for this cluster of particles.

After setting ON, remember RecomputeCollisionModel() before anim starts (it is not automatically recomputed here because of performance issues.)

◆ VariablesFbIncrementMq()

void chrono::ChMatterSPH::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.

◆ VariablesQbIncrementPosition()

void chrono::ChMatterSPH::VariablesQbIncrementPosition ( double step )

overridevirtual

Increment body position by the 'qb' part of the ChVariablesBody, 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). Does not automatically update markers & forces.

Reimplemented from chrono::ChPhysicsItem.

◆ VariablesQbLoadSpeed()

void chrono::ChMatterSPH::VariablesQbLoadSpeed ( )

overridevirtual

Initialize the 'qb' part of the ChVariablesBody with the current value of body speeds.

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

Reimplemented from chrono::ChPhysicsItem.

◆ VariablesQbSetSpeed()

void chrono::ChMatterSPH::VariablesQbSetSpeed ( double step = 0 )

overridevirtual

Fetches the body speed (both linear and angular) from the 'qb' part of the ChVariablesBody (does not updates the full body&markers state) and sets it as the current body speed.

If 'step' is not 0, also computes the approximate acceleration of the body using backward differences, that is accel=(new_speed-old_speed)/step. Mostly used after the solver provided the solution in ChVariablesBody .

Reimplemented from chrono::ChPhysicsItem.

The documentation for this class was generated from the following files:

/builds/uwsbel/chrono/src/chrono/physics/ChMatterSPH.h
/builds/uwsbel/chrono/src/chrono/physics/ChMatterSPH.cpp

Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ ChMatterSPH()

Member Function Documentation

◆ ArchiveOUT()

◆ FillBox()

◆ GetCollide()

◆ IntFromDescriptor()

◆ IntLoadResidual_F()

◆ IntLoadResidual_Mv()

◆ IntStateGather()

◆ IntStateGatherAcceleration()

◆ IntStateScatter()

◆ IntStateScatterAcceleration()

◆ IntToDescriptor()

◆ ResizeNnodes()

◆ SetCollide()

◆ VariablesFbIncrementMq()

◆ VariablesQbIncrementPosition()

◆ VariablesQbLoadSpeed()

◆ VariablesQbSetSpeed()