HertzianViscoelasticNormalSpecies contains the parameters used to describe a Hertzian normal force (The Mindlin model). More...

#include <HertzianViscoelasticNormalSpecies.h>

Inheritance diagram for HertzianViscoelasticNormalSpecies:

Public Types
typedef HertzianViscoelasticInteraction	InteractionType
	The correct Interaction type for this FrictionForceSpecies. More...

Public Member Functions
	HertzianViscoelasticNormalSpecies ()
	The default constructor. More...

	HertzianViscoelasticNormalSpecies (const HertzianViscoelasticNormalSpecies &p)
	The default copy constructor. More...

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

void	read (std::istream &is)
	Reads the species properties from an input stream. More...

void	write (std::ostream &os) const
	Writes the species properties to an output stream. More...

std::string	getBaseName () const
	Used in Species::getName to obtain a unique name for each Species. More...

Mdouble	getCollisionTime (Mdouble particleDiameter, Mdouble particleDensity, Mdouble relativeVelocity) const
	Used in Species::getName to obtain a unique name for each Species. More...

void	mix (HertzianViscoelasticNormalSpecies const SBase, HertzianViscoelasticNormalSpecies const TBase)
	Calculates collision time for two copies of a particle of given disp, k, mass. More...

void	setElasticModulus (Mdouble elasticModulus)
	Allows the spring constant to be changed. More...

void	setElasticModulusAndRestitutionCoefficient (Mdouble elasticModulus, Mdouble rest)
	Allows the spring constant to be changed. More...

Mdouble	getElasticModulus () const
	Allows the spring constant to be accessed. More...

void	setDissipation (Mdouble dissipation)
	Allows the normal dissipation to be changed. More...

Mdouble	getDissipation () const
	Allows the normal dissipation to be accessed. More...

Public Member Functions inherited from BaseSpecies
	BaseSpecies ()
	The default constructor. More...

	BaseSpecies (const BaseSpecies &p)
	The copy constructor. More...

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

virtual BaseSpecies *	copy () const =0
	Creates a deep copy of the object from which it is called. More...

void	setHandler (SpeciesHandler *handler)
	Sets the pointer to the handler to which this species belongs. More...

SpeciesHandler *	getHandler () const
	Returns the pointer to the handler to which this species belongs. More...

Mdouble	average (Mdouble a, Mdouble b)
	defines the average of two variables by the harmonic mean. More...

virtual void	mixAll (BaseSpecies const S, BaseSpecies const T)=0
	creates default values for mixed species More...

virtual Mdouble	getInteractionDistance () const =0
	returns the largest separation distance at which adhesive short-range forces can occur. More...

virtual bool	getUseAngularDOFs () const =0
	Returns true if torques (i.e. angular degrees of freedom) have to be calculated. More...

virtual BaseInteraction *	getNewInteraction (BaseInteractable P, BaseInteractable I, Mdouble timeStamp) const =0
	returns new Interaction object. 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 std::string	getName () const =0
	A purely virtual function. 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	elasticModulus_
	normal spring constant More...

Mdouble	dissipation_
	normal dissipation constant More...

Detailed Description

HertzianViscoelasticNormalSpecies contains the parameters used to describe a Hertzian normal force (The Mindlin model).

See HertzianViscoelasticNormalInteraction::computeForce for a description of the force law.

Definition at line 36 of file HertzianViscoelasticNormalSpecies.h.

Member Typedef Documentation

typedef HertzianViscoelasticInteraction HertzianViscoelasticNormalSpecies::InteractionType

The correct Interaction type for this FrictionForceSpecies.

Definition at line 40 of file HertzianViscoelasticNormalSpecies.h.

Constructor & Destructor Documentation

HertzianViscoelasticNormalSpecies::HertzianViscoelasticNormalSpecies ( )

The default constructor.

Definition at line 35 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_, and elasticModulus_.

 {
     elasticModulus_ = 0;
     dissipation_ = 0;
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"HertzianViscoelasticNormalSpecies::HertzianViscoelasticNormalSpecies() finished"<<std::endl;
 #endif
 }

HertzianViscoelasticNormalSpecies::HertzianViscoelasticNormalSpecies ( const HertzianViscoelasticNormalSpecies & p )

The default copy constructor.

Parameters

[in] the species that is copied

Definition at line 47 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_, and elasticModulus_.

 {
     elasticModulus_ = p.elasticModulus_;
     dissipation_ = p.dissipation_;
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"HertzianViscoelasticNormalSpecies::HertzianViscoelasticNormalSpecies(const HertzianViscoelasticNormalSpecies &p) finished"<<std::endl;
 #endif
 }

HertzianViscoelasticNormalSpecies::~HertzianViscoelasticNormalSpecies ( )

virtual

The default destructor.

Definition at line 56 of file HertzianViscoelasticNormalSpecies.cc.

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

Member Function Documentation

std::string HertzianViscoelasticNormalSpecies::getBaseName ( ) const

Used in Species::getName to obtain a unique name for each Species.

Returns: a string containing the name of the species (minus the word "Species")

Definition at line 85 of file HertzianViscoelasticNormalSpecies.cc.

 {
     return "HertzianViscoelastic";
 }

Mdouble HertzianViscoelasticNormalSpecies::getCollisionTime	(	Mdouble	particleDiameter,
		Mdouble	particleDensity,
		Mdouble	relativeVelocity
	)		const

Used in Species::getName to obtain a unique name for each Species.

Definition at line 219 of file HertzianViscoelasticNormalSpecies.cc.

References getElasticModulus(), and mathsFunc::square().

                                                                                                                                              {
     // Here is a very nice paper describing contact modelling
     // http://people.ds.cam.ac.uk/jae1001/CUS/research/pfizer/Antypov_Elliott_EPL_2011.pdf
     //caution: this function assumes the contact is elastic (no dissipation)
     //Mdouble omega0 = 2.0/constants::sqrt_pi*sqrt(getElasticModulus()/particleDensity)/relativeVelocity;
     //Mdouble omega1 = sqrt(omega0*omega0-getDissipation()*getDissipation());
     return 2.214*pow(mathsFunc::square(particleDensity/getElasticModulus())/relativeVelocity,0.2)*particleDiameter;
 }

Mdouble HertzianViscoelasticNormalSpecies::getDissipation ( ) const

Allows the normal dissipation to be accessed.

Definition at line 141 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_.

Referenced by HertzianViscoelasticInteraction::computeNormalForce(), and mix().

 {
     return dissipation_;
 }

Mdouble HertzianViscoelasticNormalSpecies::getElasticModulus ( ) const

Allows the spring constant to be accessed.

Definition at line 121 of file HertzianViscoelasticNormalSpecies.cc.

References elasticModulus_.

Referenced by HertzianViscoelasticInteraction::computeNormalForce(), getCollisionTime(), HertzianViscoelasticInteraction::getElasticEnergy(), HertzianViscoelasticInteraction::getElasticEnergyAtEquilibrium(), and mix().

 {
     return elasticModulus_;
 }

void HertzianViscoelasticNormalSpecies::mix	(	HertzianViscoelasticNormalSpecies *const	S,
		HertzianViscoelasticNormalSpecies *const	T
	)

Calculates collision time for two copies of a particle of given disp, k, mass.

Calculates restitution coefficient for two copies of given disp, k, masscreates default values for mixed species

For all parameters we assume that the harmonic mean of the parameters of the original two species is a sensible default.

Parameters

[in] S,T the two species whose properties are mixed to create the new species

Definition at line 213 of file HertzianViscoelasticNormalSpecies.cc.

References BaseSpecies::average(), dissipation_, elasticModulus_, getDissipation(), and getElasticModulus().

 {
     elasticModulus_ = average(S->getElasticModulus(), T->getElasticModulus());
     dissipation_ = average(S->getDissipation(), T->getDissipation());
 }

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

virtual

Reads the species properties from an input stream.

Parameters

[in] input stream (typically the restart file)

Implements BaseObject.

Definition at line 75 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_, and elasticModulus_.

 {
     std::string dummy;
     is >> dummy >> elasticModulus_
             >> dummy >> dissipation_;
 }

void HertzianViscoelasticNormalSpecies::setDissipation ( Mdouble dissipation )

Allows the normal dissipation to be changed.

Definition at line 127 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_.

 {
     if (dissipation >= 0)
     {
         dissipation_ = dissipation;
     }
     else
     {
         std::cerr << "Error in setDissipation(" << dissipation << ")" << std::endl;
         exit(-1);
     }
 }

void HertzianViscoelasticNormalSpecies::setElasticModulus ( Mdouble elasticModulus )

Allows the spring constant to be changed.

Definition at line 91 of file HertzianViscoelasticNormalSpecies.cc.

References elasticModulus_.

 {
     if (elasticModulus >= 0)
         elasticModulus_ = elasticModulus;
     else
     {
         std::cerr << "Error in setElasticModulus" << std::endl;
         exit(-1);
     }
 }

void HertzianViscoelasticNormalSpecies::setElasticModulusAndRestitutionCoefficient	(	Mdouble	elasticModulus,
		Mdouble	rest
	)

Allows the spring constant to be changed.

Definition at line 103 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_, elasticModulus_, ERROR, INFO, mathsFunc::log(), logger, and constants::sqr_pi.

                                                                                                                        {
     // Here is a very nice paper describing contact modelling
     // http://people.ds.cam.ac.uk/jae1001/CUS/research/pfizer/Antypov_Elliott_EPL_2011.pdf
     // see also: https://answers.launchpad.net/yade/+question/235934
     if (elasticModulus >= 0.0 && rest > 0.0 && rest <= 1.0)
     {
         elasticModulus_ = elasticModulus;
         Mdouble logRestSquared = log(rest)*log(rest);
         dissipation_ = sqrt(5.0 * logRestSquared / (logRestSquared + constants::sqr_pi));
         logger(INFO,"Dissipation % set to match restitution coefficient % logE % sqrPi %",dissipation_,rest,log(rest),constants::sqr_pi);
     }
     else
     {
         logger(ERROR,"Error in setElasticModulusAndRestitutionCoefficient");
     }
 }

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

virtual

Writes the species properties to an output stream.

Parameters

[out] output stream (typically the restart file)

Implements BaseObject.

Definition at line 66 of file HertzianViscoelasticNormalSpecies.cc.

References dissipation_, and elasticModulus_.

         {
     os << " stiffness " << elasticModulus_
             << " dissipation " << dissipation_;
 }

Member Data Documentation

Mdouble HertzianViscoelasticNormalSpecies::dissipation_

private

normal dissipation constant

Definition at line 113 of file HertzianViscoelasticNormalSpecies.h.

Referenced by getDissipation(), HertzianViscoelasticNormalSpecies(), mix(), read(), setDissipation(), setElasticModulusAndRestitutionCoefficient(), and write().

Mdouble HertzianViscoelasticNormalSpecies::elasticModulus_

private

normal spring constant

Definition at line 110 of file HertzianViscoelasticNormalSpecies.h.

Referenced by getElasticModulus(), HertzianViscoelasticNormalSpecies(), mix(), read(), setElasticModulus(), setElasticModulusAndRestitutionCoefficient(), and write().

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

Species/NormalForceSpecies/HertzianViscoelasticNormalSpecies.h
Species/NormalForceSpecies/HertzianViscoelasticNormalSpecies.cc

Public Types

Public Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation