Computes normal forces in case of a linear plastic visco-elastic interaction. More...

#include <SinterInteraction.h>

Inheritance diagram for SinterInteraction:

Public Types
typedef SinterNormalSpecies	SpeciesType
	An alias for the corresponding species. More...

Public Member Functions
	SinterInteraction (BaseInteractable P, BaseInteractable I, Mdouble timeStamp)
	Constructor. More...

	SinterInteraction (const SinterInteraction &p)
	Copy constructor. More...

virtual	~SinterInteraction ()
	Destructor. More...

void	computeNormalForce ()
	Creates a copy of an object of this class. (Deep copy) More...

virtual void	read (std::istream &is)
	Interaction read function, which accepts an std::istream as input. More...

virtual void	write (std::ostream &os) const
	Interaction write function, which accepts an std::ostream as input. More...

virtual std::string	getBaseName () const
	Returns the name of the interaction. More...

Mdouble	getElasticEnergy () const
	Computes and returns the amount of elastic energy stored in the spring. More...

const SinterNormalSpecies *	getSpecies () const

Mdouble	getPlasticOverlap () const

void	setPlasticOverlap (const Mdouble plasticOverlap)

Mdouble	getUnloadingStiffness () const

unsigned	getNumberOfFieldsVTK () const override

std::string	getTypeVTK (unsigned i) const override

std::string	getNameVTK (unsigned i) const override

std::vector< Mdouble >	getFieldVTK (unsigned i) const override

Public Member Functions inherited from BaseInteraction
	BaseInteraction (BaseInteractable P, BaseInteractable I, Mdouble timeStamp)
	A constructor takes the BaseInteractable objects which are interacting (come into contact) and time the interaction starts. More...

	BaseInteraction (const BaseInteraction &p)
	Copy constructor. More...

	BaseInteraction ()
	Empty constructor. More...

virtual	~BaseInteraction ()
	The default destructor. More...

virtual void	actionsOnErase ()
	If an interaction needs to do something before it gets erased, add it here. E.g. Liquid bridges rupture at the end of their lifetime, and the liquid bridge volume has to be redistributed. The reason this action is not done in the destructor is that this action should not be taken when erasing ghost interactions. More...

virtual void	computeForce ()
	Virtual function that contains the force law between the two objects interacting. More...

void	writeToFStat (std::ostream &os) const
	Writes forces data to the FStat file. More...

virtual std::string	getName () const
	Virtual function which allows interactions to be named. More...

void	setDistance (Mdouble distance)
	Sets the interaction distance between the two interacting objects. More...

void	setNormal (Vec3D normal)
	Sets the normal vector between the two interacting objects. More...

void	setOverlap (Mdouble overlap)
	Set the overlap between the two interacting object. More...

void	setContactPoint (Vec3D contactPoint)
	Set the location of the contact point between the two interacting objects. More...

void	setTimeStamp (Mdouble timeStamp)
	Updates the time step of the interacting. Note, timesteps used to find completed interactions. More...

void	setSpecies (BaseSpecies *species)
	Set the Species of the interaction; note this can either be a Species or MixedSpecies. More...

void	setP (BaseInteractable *P)
	Sets the first object involved in the interaction (normally a particle). More...

void	setI (BaseInteractable *I)
	Sets the second object involved in the interaction (often particle or wall). More...

void	setHandler (InteractionHandler *handler)
	Sets the pointer to the interaction hander which is storing this interaction. More...

InteractionHandler *	getHandler () const
	Gets a point to the interaction handlers to which this interaction belongs. More...

const Vec3D &	getForce () const
	Gets the current force (vector) between the two interacting objects. More...

const Vec3D &	getTorque () const
	Gets the current torque (vector) between the two interacting objects. More...

const Vec3D &	getNormal () const
	Gets the normal vector between the two interacting objects. More...

const Vec3D &	getContactPoint () const
	Gets constant reference to contact point (vector). More...

Mdouble	getOverlap () const
	Returns a Mdouble with the current overlap between the two interacting objects. More...

Mdouble	getContactRadius () const
	Returns a Mdouble with the current contact between the two interacting objects. More...

void	removeFromHandler ()
	Removes this interaction from its interaction hander. More...

void	copySwitchPointer (const BaseInteractable original, BaseInteractable ghost) const
	This copies the interactions of the original particle and replaces the original with the ghost copy. More...

void	gatherContactStatistics ()

BaseInteractable *	getP ()
	Returns a pointer to first object involved in the interaction (normally a particle). More...

BaseInteractable *	getI ()

const BaseInteractable *	getP () const

const BaseInteractable *	getI () const
	Returns a constant pointer to the second object involved in the interaction. More...

Mdouble	getTimeStamp () const
	Returns an Mdouble which is the time stamp of the interaction. More...

virtual void	integrate (Mdouble timeStep)
	integrates variables of the interaction which need to be integrate e.g. the tangential overlap. More...

virtual Mdouble	getTangentialOverlap () const
	get the length of the current tangential overlap More...

Mdouble	getDistance () const
	Returns an Mdouble which is the norm (length) of distance vector. More...

const Vec3D &	getRelativeVelocity () const
	Returns a constant reference to a vector of relative velocity. More...

Mdouble	getNormalRelativeVelocity () const
	Returns a double which is the norm (length) of the relative velocity vector. More...

Mdouble	getAbsoluteNormalForce () const
	Returns the absolute value of the norm (length) of the Normal force vector. More...

virtual BaseInteraction *	copy () const =0
	Makes a copy of the interaction and returns a pointer to the copy. More...

unsigned int	getMultiContactIdentifier () const

void	setMultiContactIdentifier (unsigned int multiContactIdentifier_)

virtual void	rotateHistory (Matrix3D &rotationMatrix)
	When periodic particles are used, some interactions need certain history properties rotated (e.g. tangential springs). This is the function for that. More...

virtual void	actionsAfterTimeStep ()

void	setForce (Vec3D force)
	set total force (this is used by the normal force, tangential forces are added use addForce) More...

Public Member Functions inherited from BaseObject
	BaseObject ()
	Default constructor. More...

	BaseObject (const BaseObject &p)
	Copy constructor, copies all the objects BaseObject contains. More...

virtual	~BaseObject ()
	virtual destructor More...

virtual void	moveInHandler (const unsigned int index)
	Except that it is virtual, it does the same thing as setIndex() does. More...

void	setIndex (const unsigned int index)
	Allows one to assign an index to an object in the handler/container. More...

void	setId (const unsigned int id)
	Assigns a unique identifier to each object in the handler (container) which remains constant even after the object is deleted from the container/handler. More...

unsigned int	getIndex () const
	Returns the index of the object in the handler. More...

unsigned int	getId () const
	Returns the unique identifier of any particular object. More...

Private Attributes
Mdouble	plasticOverlap_

Additional Inherited Members
Protected Member Functions inherited from BaseInteraction
virtual const Vec3D	getTangentialForce () const

Mdouble	getEffectiveRadius () const
	Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) More...

Mdouble	getEffectiveMass () const
	Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) More...

Mdouble	getEffectiveCorrectedRadius ()
	Returns a Mdouble to the effective radius corrected for the overlaps of the particles. More...

void	addForce (Vec3D force)
	add an force increment to the total force. More...

void	addTorque (Vec3D torque)

void	setTorque (Vec3D torque)
	set the total force (this is used by the normal force, tangential torques are added use addTorque) More...

void	setRelativeVelocity (Vec3D relativeVelocity)
	set the relative velocity of the current of the interactions. More...

void	setNormalRelativeVelocity (Mdouble normalRelativeVelocit)
	set the normal component of the relative velocity. More...

void	setAbsoluteNormalForce (Mdouble absoluteNormalForce)
	the absolute values of the norm (length) of the normal force More...

const BaseSpecies *	getBaseSpecies () const
	Return a constant point to BaseSpecies of the interaction. More...

virtual Mdouble	getElasticEnergyAtEquilibrium (Mdouble adhesiveForce) const

virtual void	reverseHistory ()
	When periodic particles some interaction need certain history properties reversing. This is the function for that. More...

Detailed Description

Computes normal forces in case of a linear plastic visco-elastic interaction.

Definition at line 36 of file SinterInteraction.h.

Member Typedef Documentation

typedef SinterNormalSpecies SinterInteraction::SpeciesType

An alias for the corresponding species.

Definition at line 42 of file SinterInteraction.h.

Constructor & Destructor Documentation

SinterInteraction::SinterInteraction	(	BaseInteractable *	P,
		BaseInteractable *	I,
		Mdouble	timeStamp
	)

Constructor.

Parameters

[in]	P
[in]	I
[in]	timeStamp

Definition at line 39 of file SinterInteraction.cc.

References plasticOverlap_.

         : BaseInteraction(P, I, timeStamp)
 {
     plasticOverlap_=0;
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"SinterInteraction::SinterInteraction() finished"<<std::endl;
 #endif
 }

SinterInteraction::SinterInteraction ( const SinterInteraction & p )

Copy constructor.

Parameters

[in] p

Definition at line 50 of file SinterInteraction.cc.

References plasticOverlap_.

         : BaseInteraction(p)
 {
     plasticOverlap_=p.plasticOverlap_;
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"SinterInteraction::SinterInteraction(const SinterInteraction &p finished"<<std::endl;
 #endif
 }

SinterInteraction::~SinterInteraction ( )

virtual

Destructor.

Definition at line 61 of file SinterInteraction.cc.

 {
 #ifdef DEBUG_DESTRUCTOR
     std::cout<<"SinterInteraction::~SinterInteraction() finished"<<std::endl;
 #endif
 }

Member Function Documentation

void SinterInteraction::computeNormalForce ( )

Creates a copy of an object of this class. (Deep copy)

Computes the normal forces due to linear plastic visco elastic interaction.

Todo:: basing the stiffness increase on the plastic overlap does not work: k2*(d-d0)=k1*d, k2=k1*(1+dk*d0) (1+dk*d0)*(d-d0)=d d+dk*d*d0-d0-dk*d0*d0=d -dk*d0^2+(dk*d-1)*d0+d=d d0=(dk*d-1)/dk

Todo:: adhesive force only, or add normalForce?

Definition at line 98 of file SinterInteraction.cc.

 {
     // Compute the relative velocity vector of particle P w.r.t. I
     setRelativeVelocity(getP()->getVelocityAtContact(getContactPoint()) - getI()->getVelocityAtContact(getContactPoint()));
     // Compute the projection of vrel onto the normal (can be negative)
     setNormalRelativeVelocity(Vec3D::dot(getRelativeVelocity(), getNormal()));
 
     if (getOverlap() > 0) //if contact forces
     {
         const SinterNormalSpecies* species = getSpecies();
         // calculate the effective diameter, equal to the radius for two equal-sized particles
         const Mdouble effectiveDiameter = 2.0 * getEffectiveRadius();
         //calculate the overlap above which the max. unloading stiffness 
         //becomes active (the 'fluid branch')
         const Mdouble deltaStar = species->getPenetrationDepthMax() * effectiveDiameter;
         //compute the rate d(k2/k1)/d(delta0)
         const Mdouble dk = (species->getUnloadingStiffnessMax()/species->getLoadingStiffness() - 1.0)/deltaStar;
 
         //increase max overlap if necessary
         //k2*(d-d0)=k1*d, k2=k1*(1+dk*d)
         //(1+dk*d)*(d-d0)=d
         //dk*d^2=(1+dk*d)*d0
         //d0=d/(1+1/(dk*d))
         const Mdouble minPlasticOverlap = std::min(getOverlap()/(1.0+1.0/(dk*getOverlap())),deltaStar);
         //const Mdouble minPlasticOverlap = std::min(getOverlap()-1.0/dk,deltaStar);
         //logger(INFO,"minPlasticOverlap % overlap % dk % M %",minPlasticOverlap,getOverlap(),dk, dk*getOverlap());
         plasticOverlap_ = std::max(minPlasticOverlap,plasticOverlap_);
         
         //calculate the unloading stiffness (only linear in maxOverlap, not equilibriumOverlap))
         const Mdouble unloadingStiffness = species->getLoadingStiffness() * (1.0+dk*plasticOverlap_);
         
         //compute elastic force
         Mdouble normalForce = unloadingStiffness * (getOverlap() - plasticOverlap_);
                 
         //add cohesive forces (distinct from sintering)
         Mdouble nonSinterAdhesiveForce = -species->getCohesionStiffness() * getOverlap();
         if (normalForce < nonSinterAdhesiveForce) {
             plasticOverlap_ = (1.0 + species->getCohesionStiffness()/unloadingStiffness)*getOverlap();
             normalForce = nonSinterAdhesiveForce;
         }
 
         //add dissipative force (distinct from sintering)
         normalForce -= species->getDissipation() * getNormalRelativeVelocity();
 
         //Here comes the sintering effect:
         Mdouble adhesiveForce = species->getSinterAdhesion()*effectiveDiameter;
 
         //now set the interaction force equal to this normal force (friction and adhesive forces will be added later)
         setForce(getNormal() * ((normalForce-adhesiveForce)));
         setTorque(Vec3D(0.0, 0.0, 0.0));
         //used for tangential force calculations; don't add adhesive force components
         setAbsoluteNormalForce(std::abs(normalForce));
 
         //increase plastic overlap due to sintering
         DPMBase* dpmBase  = getHandler()->getDPMBase();
         Mdouble rateOverlap;
         // sinter adhesion force fa=sinterAdhesion_*radius in sinter rate:
         if (species->getSinterType()==SINTERTYPE::PARHAMI_MCKEEPING) {
             rateOverlap = normalForce*species->getSinterRate()/
              (0.375*species->getSinterAdhesion()*mathsFunc::square(getOverlap()/effectiveDiameter)); 
             if (species->getSinterRate()==0) rateOverlap = 0;
         } else if (species->getSinterType()==SINTERTYPE::CONSTANT_RATE) {
             rateOverlap = 2.0*normalForce*species->getSinterRate()/species->getSinterAdhesion();
             if (species->getSinterRate()==0) rateOverlap = 0;
         } else if (species->getSinterType()==SINTERTYPE::TEMPERATURE_DEPENDENT_FRENKEL) {
             ThermalParticle* tp = dynamic_cast<ThermalParticle*>(getP());
             ThermalParticle* ti = dynamic_cast<ThermalParticle*>(getI());
             logger.assert(tp && ti,"warning contact partners have to be ThermalParticle's if this sinter species is used");
             double temperature = 2.0*tp->getTemperature()*ti->getTemperature()/(tp->getTemperature()+ti->getTemperature());
             rateOverlap = 2.0*normalForce*species->getTemperatureDependentSinterRate(temperature)/species->getSinterAdhesion();
         } else {
             //missing: add the sintering model 'modified Frenkel' of the Pokula paper
         }
         plasticOverlap_ = std::max(0.0,std::min(deltaStar,plasticOverlap_+rateOverlap*dpmBase->getTimeStep()));
 
         /*//change particle radius by dr
         Mdouble dr;
         BaseParticle* PParticle = dynamic_cast<BaseParticle*>(getP());
         BaseParticle* IParticle = dynamic_cast<BaseParticle*>(getI());
         if (dpmBase->getSystemDimensions()==2) {
             //2D: increase the radius of each particle such that the particle area
             //increases by the same amount that the contact area decreases
             //Particle circumference C = 2 pi r increased by dr => dA = 2 pi r dr
             //Contact line L = 2*sqrt(2*r*o) indented by do/2 => dA = sqrt(2*r*o) do
             //Thus, dr = sqrt(0.5*o/r)/pi do.
             dr = sqrt(0.5*plasticOverlap_/effectiveDiameter)/3.14 *doverlap;
         } else {
             //3D: increase the radius of each sphere such that the particle volume
             //increases by the same amount that the contact volume decreases
             //Particle surface area S = 4 pi r^2 increased by dr => dA = 4 pi r^2 dr
             //Contact area L = pi 2*r*o indented by do/2 => dA = pi r o do
             //Thus, dr = 0.25*o/r do
             dr = 0.25*plasticOverlap_/effectiveDiameter *doverlap;
         }
         if (PParticle==nullptr) { //if P is a wall
             IParticle->setRadius(IParticle->getRadius()+dr);//should be twice that amount
         } else if (IParticle==nullptr) { //if I is a wall
             PParticle->setRadius(PParticle->getRadius()+dr);
         } else { //if both P and I are particles
             PParticle->setRadius(PParticle->getRadius()+dr);
             IParticle->setRadius(IParticle->getRadius()+dr);
         }*/
     }
     else
     {
         setAbsoluteNormalForce(0.0);
         setForce(Vec3D(0.0, 0.0, 0.0));
         setTorque(Vec3D(0.0, 0.0, 0.0));
     } 
 }

std::string SinterInteraction::getBaseName ( ) const

virtual

Returns the name of the interaction.

Returns: std::string

Definition at line 90 of file SinterInteraction.cc.

 {
     return "Sinter";
 }

Mdouble SinterInteraction::getElasticEnergy ( ) const

virtual

Computes and returns the amount of elastic energy stored in the spring.

Returns: Mdouble

Todo:: TW this is not correct; we should count the return energy

Reimplemented from BaseInteraction.

Definition at line 218 of file SinterInteraction.cc.

References SinterNormalSpecies::getLoadingStiffness(), BaseInteraction::getOverlap(), getSpecies(), and mathsFunc::square().

 {
    if (getOverlap() > 0)
         return 0.5 * (getSpecies()->getLoadingStiffness() * mathsFunc::square(getOverlap()));
     else
         return 0.0;
 }

std::vector< Mdouble > SinterInteraction::getFieldVTK ( unsigned i ) const

overridevirtual

Reimplemented from BaseInteraction.

Definition at line 277 of file SinterInteraction.cc.

References BaseInteraction::getEffectiveRadius(), and plasticOverlap_.

                                                                   {
     if (i==0)
         return std::vector<Mdouble>(1, plasticOverlap_);
     else
         return std::vector<Mdouble>(1, sqrt(2.0*getEffectiveRadius()*plasticOverlap_));
 }

std::string SinterInteraction::getNameVTK ( unsigned i ) const

overridevirtual

Reimplemented from BaseInteraction.

Definition at line 270 of file SinterInteraction.cc.

                                                         {
     if (i==0)
         return "plasticOverlap";
     else
         return "neckRadius";
 }

unsigned SinterInteraction::getNumberOfFieldsVTK ( ) const

overridevirtual

Reimplemented from BaseInteraction.

Definition at line 262 of file SinterInteraction.cc.

                                                        {
     return 2;
 }

Mdouble SinterInteraction::getPlasticOverlap ( ) const

Returns: Mdouble plasticOverlap_

Definition at line 236 of file SinterInteraction.cc.

References plasticOverlap_.

Referenced by getUnloadingStiffness().

 {
     return plasticOverlap_;
 }

const SinterNormalSpecies * SinterInteraction::getSpecies ( ) const

Returns: const SinterNormalSpecies*

Definition at line 229 of file SinterInteraction.cc.

References BaseInteraction::getBaseSpecies().

Referenced by computeNormalForce(), getElasticEnergy(), and getUnloadingStiffness().

 {
     return dynamic_cast<const SinterNormalSpecies*>(getBaseSpecies());
 }

std::string SinterInteraction::getTypeVTK ( unsigned i ) const

overridevirtual

Reimplemented from BaseInteraction.

Definition at line 266 of file SinterInteraction.cc.

                                                         {
     return "Float32";
 }

Mdouble SinterInteraction::getUnloadingStiffness ( ) const

Returns: Mdouble

Definition at line 250 of file SinterInteraction.cc.

References BaseInteraction::getEffectiveRadius(), SinterNormalSpecies::getLoadingStiffness(), BaseInteraction::getOverlap(), SinterNormalSpecies::getPenetrationDepthMax(), getPlasticOverlap(), getSpecies(), and SinterNormalSpecies::getUnloadingStiffnessMax().

 {
     const SinterNormalSpecies* species = getSpecies();
     Mdouble effectiveDiameter = 2.0*getEffectiveRadius();
     Mdouble deltaMaxFluid = species->getPenetrationDepthMax() * effectiveDiameter / (1.0-species->getLoadingStiffness()/species->getUnloadingStiffnessMax());
     if (getOverlap() > deltaMaxFluid)
         return species->getUnloadingStiffnessMax();
     else
         return species->getLoadingStiffness() + (species->getUnloadingStiffnessMax() - species->getLoadingStiffness()) *
                                                 getPlasticOverlap()/deltaMaxFluid;
 }

void SinterInteraction::read ( std::istream & is )

virtual

Interaction read function, which accepts an std::istream as input.

Calls the read function of BaseInteraction().

Parameters

[in,out] is

Reimplemented from BaseInteraction.

Definition at line 81 of file SinterInteraction.cc.

References plasticOverlap_, and BaseInteraction::read().

 {
     BaseInteraction::read(is);
     std::string dummy;
     is >> dummy >> plasticOverlap_;
 }

void SinterInteraction::setPlasticOverlap ( const Mdouble plasticOverlap )

Parameters

[in] maxOverlap

Definition at line 243 of file SinterInteraction.cc.

References plasticOverlap_.

 {
     plasticOverlap_ = plasticOverlap;
 }

void SinterInteraction::write ( std::ostream & os ) const

virtual

Interaction write function, which accepts an std::ostream as input.

Calls the write function of BaseInteraction().

Parameters

[in,out] os

Reimplemented from BaseInteraction.

Definition at line 72 of file SinterInteraction.cc.

References plasticOverlap_, and BaseInteraction::write().

 {
     BaseInteraction::write(os);
     os << " plasticOverlap " << plasticOverlap_;
 }

Member Data Documentation

Mdouble SinterInteraction::plasticOverlap_

private

Definition at line 107 of file SinterInteraction.h.

Referenced by computeNormalForce(), getFieldVTK(), getPlasticOverlap(), read(), setPlasticOverlap(), SinterInteraction(), and write().

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

Interactions/NormalForceInteractions/SinterInteraction.h
Interactions/NormalForceInteractions/SinterInteraction.cc

Public Types

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation