MindlinSpecies contains the parameters used to describe sliding friction. More...

#include <MindlinSpecies.h>

Inheritance diagram for MindlinSpecies:

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

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

	MindlinSpecies (const MindlinSpecies &s)
	The default copy constructor. More...

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

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

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

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

void	setSlidingDissipation (Mdouble new_dispt)
	Allows the tangential viscosity to be changed. More...

Mdouble	getSlidingDissipation () const
	Allows the tangential viscosity to be accessed. More...

void	setSlidingFrictionCoefficient (Mdouble new_mu)
	Allows the (dynamic) Coulomb friction coefficient to be changed; also sets mu_s by default. More...

void	setShearModulus (Mdouble new_G)

Mdouble	getShearModulus () const

Mdouble	getSlidingFrictionCoefficient () const
	Allows the (dynamic) Coulomb friction coefficient to be accessed. More...

void	setSlidingFrictionCoefficientStatic (Mdouble new_mu)
	Allows the static Coulomb friction coefficient to be changed. More...

Mdouble	getSlidingFrictionCoefficientStatic () const
	Allows the static Coulomb friction coefficient to be accessed. More...

bool	getUseAngularDOFs () const override
	Returns true if torques have to be calculated. More...

void	mix (MindlinSpecies const S, MindlinSpecies const T)
	creates default values for mixed species 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 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	slidingDissipation_
	tangential dissipation coefficient. More...

Mdouble	slidingFrictionCoefficient_
	(dynamic) Coulomb friction coefficient More...

Mdouble	slidingFrictionCoefficientStatic_
	static Coulomb friction coefficient (by default set equal to mu) More...

Mdouble	shearModulus_

Detailed Description

MindlinSpecies contains the parameters used to describe sliding friction.

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

Definition at line 36 of file MindlinSpecies.h.

Member Typedef Documentation

typedef MindlinInteraction MindlinSpecies::InteractionType

The correct Interaction type for this FrictionForceSpecies.

Definition at line 40 of file MindlinSpecies.h.

Constructor & Destructor Documentation

MindlinSpecies::MindlinSpecies ( )

The default constructor.

Definition at line 35 of file MindlinSpecies.cc.

References shearModulus_, slidingDissipation_, slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

 {
     slidingDissipation_ = 0;
     slidingFrictionCoefficient_ = 0;
     slidingFrictionCoefficientStatic_ = 0;
     //k_edit
     //setting the shear modulus to have a default value of zero, in-keeping with the other parameters...
     shearModulus_ = 0;
     //...and the same for K_t0
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"MindlinSpecies::MindlinSpecies() finished"<<std::endl;
 #endif
 }

MindlinSpecies::MindlinSpecies ( const MindlinSpecies & s )

The default copy constructor.

Parameters

[in] s the species that is copied

Definition at line 52 of file MindlinSpecies.cc.

References shearModulus_, slidingDissipation_, slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

 {
     slidingDissipation_ = s.slidingDissipation_;
     slidingFrictionCoefficient_ = s.slidingFrictionCoefficient_;
     slidingFrictionCoefficientStatic_ = s.slidingFrictionCoefficientStatic_;
     //k_edit
     //setting the shear modulus to the value of 's', in-keeping with the other parameters...
     shearModulus_ = s.shearModulus_;
 #ifdef DEBUG_CONSTRUCTOR
     std::cout<<"MindlinSpecies::MindlinSpecies(const MindlinSpecies &p) finished"<<std::endl;
 #endif
 }

MindlinSpecies::~MindlinSpecies ( )

virtual

The default destructor.

Definition at line 65 of file MindlinSpecies.cc.

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

Member Function Documentation

std::string MindlinSpecies::getBaseName ( ) const

virtual

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")

Reimplemented in MindlinRollingTorsionSpecies.

Definition at line 101 of file MindlinSpecies.cc.

 {
     return "Mindlin";
 }

Mdouble MindlinSpecies::getShearModulus ( ) const

Definition at line 177 of file MindlinSpecies.cc.

References shearModulus_.

Referenced by MindlinInteraction::computeFrictionForce().

                                               {
     return shearModulus_;
 }

Mdouble MindlinSpecies::getSlidingDissipation ( ) const

Allows the tangential viscosity to be accessed.

Definition at line 120 of file MindlinSpecies.cc.

References slidingDissipation_.

Referenced by MindlinInteraction::computeFrictionForce(), and mix().

 {
     return slidingDissipation_;
 }

Mdouble MindlinSpecies::getSlidingFrictionCoefficient ( ) const

Allows the (dynamic) Coulomb friction coefficient to be accessed.

Definition at line 142 of file MindlinSpecies.cc.

References slidingFrictionCoefficient_.

Referenced by MindlinInteraction::computeFrictionForce(), and mix().

 {
     return slidingFrictionCoefficient_;
 }

Mdouble MindlinSpecies::getSlidingFrictionCoefficientStatic ( ) const

Allows the static Coulomb friction coefficient to be accessed.

Definition at line 182 of file MindlinSpecies.cc.

References slidingFrictionCoefficientStatic_.

Referenced by mix().

 {
     return slidingFrictionCoefficientStatic_;
 }

bool MindlinSpecies::getUseAngularDOFs ( ) const

overridevirtual

Returns true if torques have to be calculated.

Returns true for any FrictionForceSpecies except EmptyFrictionSpecies, because for spherical particles, torques are only caused by tangential forces. See SpeciesHandler::useAngularDOFs for more details

Returns: true

Implements BaseSpecies.

Definition at line 193 of file MindlinSpecies.cc.

 {
     return true;
 }

void MindlinSpecies::mix	(	MindlinSpecies *const	SFrictional,
		MindlinSpecies *const	TFrictional
	)

creates 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]	SFrictional	the first species whose properties are mixed to create the new species
[in]	TFrictional	the second species whose properties are mixed to create the new species

Todo:: KWY: Add a 'mix' property for shear modulus

Definition at line 205 of file MindlinSpecies.cc.

References BaseSpecies::average(), getSlidingDissipation(), getSlidingFrictionCoefficient(), getSlidingFrictionCoefficientStatic(), slidingDissipation_, slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

 {
     slidingDissipation_ = average(SFrictional->getSlidingDissipation(), TFrictional->getSlidingDissipation());
     slidingFrictionCoefficient_ = average(SFrictional->getSlidingFrictionCoefficient(), TFrictional->getSlidingFrictionCoefficient());
     slidingFrictionCoefficientStatic_ = average(SFrictional->getSlidingFrictionCoefficientStatic(), TFrictional->getSlidingFrictionCoefficientStatic());
 }

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

overridevirtual

Reads the species properties from an input stream.

Parameters

[in] is input stream (typically the restart file)

Implements BaseObject.

Definition at line 88 of file MindlinSpecies.cc.

References shearModulus_, slidingDissipation_, slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

Referenced by MindlinRollingTorsionSpecies::read().

 {
     //BaseSpecies::read(is);
     std::string dummy;
     is >> dummy >> shearModulus_;
     is >> dummy >> slidingDissipation_;
     is >> dummy >> slidingFrictionCoefficient_;
     is >> dummy >> slidingFrictionCoefficientStatic_;
 }

void MindlinSpecies::setShearModulus ( Mdouble new_G )

Definition at line 162 of file MindlinSpecies.cc.

References shearModulus_.

                                                   {
     //sanity check to ensure that a negative shear modulus cannot be set!
     if (new_G >= 0)
     {
         shearModulus_ = new_G;
     }
     else
     {
         std::cerr << "Error in setShearModulus" << std::endl;
         exit(-1);
     }
 }

void MindlinSpecies::setSlidingDissipation ( Mdouble new_dispt )

Allows the tangential viscosity to be changed.

Definition at line 109 of file MindlinSpecies.cc.

References slidingDissipation_.

 {
     if (new_dispt >= 0)
         slidingDissipation_ = new_dispt;
     else
     {
         std::cerr << "Error in setSlidingDissipation" << std::endl;
         exit(-1);
     }
 }

void MindlinSpecies::setSlidingFrictionCoefficient ( Mdouble new_mu )

Allows the (dynamic) Coulomb friction coefficient to be changed; also sets mu_s by default.

Definition at line 127 of file MindlinSpecies.cc.

References slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

 {
     if (new_mu >= 0)
     {
         slidingFrictionCoefficient_ = new_mu;
         slidingFrictionCoefficientStatic_ = slidingFrictionCoefficient_;
     }
     else
     {
         std::cerr << "Error in setSlidingFrictionCoefficient" << std::endl;
         exit(-1);
     }
 }

void MindlinSpecies::setSlidingFrictionCoefficientStatic ( Mdouble new_mu )

Allows the static Coulomb friction coefficient to be changed.

Allows the static Coulomb friction coefficient to be changed; also sets mu_s by default.

Definition at line 148 of file MindlinSpecies.cc.

References slidingFrictionCoefficientStatic_.

 {
     if (new_mu >= 0)
     {
         slidingFrictionCoefficientStatic_ = new_mu;
     }
     else
     {
         std::cerr << "Error in setSlidingFrictionCoefficientStatic" << std::endl;
         exit(-1);
     }
 }

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

overridevirtual

Writes the species properties to an output stream.

Parameters

[out] os output stream (typically the restart file)

Implements BaseObject.

Definition at line 76 of file MindlinSpecies.cc.

References shearModulus_, slidingDissipation_, slidingFrictionCoefficient_, and slidingFrictionCoefficientStatic_.

Referenced by MindlinRollingTorsionSpecies::write().

         {
     //BaseSpecies::write(os);
     os << " shearModulus " << shearModulus_;
     os << " slidingDissipation " << slidingDissipation_;
     os << " slidingFrictionCoefficient " << slidingFrictionCoefficient_;
     os << " slidingFrictionCoefficientStatic " << slidingFrictionCoefficientStatic_;
 }

Member Data Documentation

Mdouble MindlinSpecies::shearModulus_

private

Definition at line 117 of file MindlinSpecies.h.

Referenced by getShearModulus(), MindlinSpecies(), read(), setShearModulus(), and write().

Mdouble MindlinSpecies::slidingDissipation_

private

tangential dissipation coefficient.

Typically set to 2/7 of the normal force dissipation, as both the tangential and the normal spring have the same restitution coefficients (if the tangential and normal stiffnesses also have a ratio of 2/7). should always satisfy $4*dispt*dt<mass, dispt \approx disp$ , otherwise the restitution is zero and the particles stick.