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HertzianViscoelasticInteraction Class Reference

Computes normal forces for a Herztian visco-elastic interaction. More...

#include <HertzianViscoelasticInteraction.h>

+ Inheritance diagram for HertzianViscoelasticInteraction:

Public Types

typedef
HertzianViscoelasticNormalSpecies 
SpeciesType
 An alias for HertzianViscoelasticNormalSpecies. More...
 

Public Member Functions

 HertzianViscoelasticInteraction (BaseInteractable *P, BaseInteractable *I, unsigned timeStamp)
 Constructor. More...
 
 HertzianViscoelasticInteraction ()
 
 HertzianViscoelasticInteraction (const HertzianViscoelasticInteraction &p)
 Copy constructor. More...
 
 ~HertzianViscoelasticInteraction () override
 Destructor. More...
 
void computeNormalForce ()
 Computes the amount of normal force due to an Hertzian visco-elastic interaction. More...
 
 HertzianViscoelasticInteraction (const BaseInteraction &p)
 
void read (std::istream &is) override
 Interaction read function, which accepts an std::istream as input. More...
 
void write (std::ostream &os) const override
 Interaction write function, which accepts an std::ostream as input. More...
 
std::string getBaseName () const
 Returns the name of the interaction. More...
 
Mdouble getElasticEnergy () const override
 Computes and returns the amount of elastic energy stored in the spring. More...
 
const
HertzianViscoelasticNormalSpecies
getSpecies () const
 Returns a const pointer of type HerztianViscoelasticNormalSpecies (dynamic-cast). More...
 
Mdouble getElasticEnergyAtEquilibrium (Mdouble adhesiveForce) const override
 
- Public Member Functions inherited from BaseInteraction
 BaseInteraction (BaseInteractable *P, BaseInteractable *I, unsigned timeStamp)
 A constructor takes the BaseInteractable objects which are interacting (come into contact) and time the interaction starts. More...
 
 BaseInteraction ()
 
 BaseInteraction (const BaseInteraction &p)
 Copy constructor. More...
 
 ~BaseInteraction () override
 The 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, Mdouble time) const
 Writes forces data to the FStat file. More...
 
std::string getName () const override
 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 (unsigned timeStamp)
 Updates the time step of the interacting. Note, time steps used to find completed interactions. More...
 
void setSpecies (const 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 importP (BaseInteractable *P)
 Sets the first object involved in the interaction (normally a particle). More...
 
void importI (BaseInteractable *I)
 Sets the second object involved in the interaction (often particle or wall). More...
 
Vec3D getIP () const
 
Vec3D getIC () const
 
Vec3D getCP () const
 
void setLagrangeMultiplier (Mdouble multiplier)
 
Mdouble getLagrangeMultiplier ()
 
void setHandler (InteractionHandler *handler)
 Sets the pointer to the interaction hander which is storing this interaction. More...
 
InteractionHandlergetHandler () const
 Gets a point to the interaction handlers to which this interaction belongs. More...
 
const Vec3DgetForce () const
 Gets the current force (vector) between the two interacting objects. More...
 
const Vec3DgetTorque () const
 Gets the current torque (vector) between the two interacting objects. More...
 
const Vec3DgetNormal () const
 Gets the normal vector between the two interacting objects. More...
 
const Vec3DgetContactPoint () 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 ()
 
BaseInteractablegetP ()
 Returns a pointer to first object involved in the interaction (normally a particle). More...
 
BaseInteractablegetI ()
 Returns a pointer to the second object involved in the interaction (often a wall or a particle). More...
 
const BaseInteractablegetP () const
 Returns a constant pointer to the first object involved in the interaction. More...
 
const BaseInteractablegetI () 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 Vec3DgetRelativeVelocity () 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 BaseInteractioncopy () const =0
 Makes a copy of the interaction and returns a pointer to the copy. More...
 
void setFStatData (std::fstream &fstat, BaseParticle *P, BaseWall *I)
 
void setFStatData (std::fstream &fstat, BaseParticle *P, BaseParticle *I)
 
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 ()
 
virtual unsigned getNumberOfFieldsVTK () const
 
virtual std::string getTypeVTK (unsigned i) const
 
virtual std::string getNameVTK (unsigned i) const
 
virtual std::vector< MdoublegetFieldVTK (unsigned i) const
 
void setForce (Vec3D force)
 set total force (this is used by the normal force, tangential forces are added use addForce) More...
 
const BaseSpeciesgetBaseSpecies () const
 Return a constant point to BaseSpecies of the interaction. More...
 
virtual void createMPIType ()
 
virtual void * createMPIInteractionDataArray (unsigned int numberOfInteractions) const
 
virtual void deleteMPIInteractionDataArray (void *dataArray)
 
virtual void getMPIInteraction (void *historyDataArray, unsigned int index) const
 copies the history interactions into the data array More...
 
virtual void getInteractionDetails (void *interactionDataArray, unsigned int index, unsigned int &identificationP, unsigned int &identificationI, bool &isWallInteraction, unsigned &timeStamp)
 
virtual void setMPIInteraction (void *interactionDataArray, unsigned int index, bool resetPointers)
 
void setBasicMPIInteractionValues (int P, int I, unsigned timeStamp, Vec3D force, Vec3D torque, bool isWallInteraction, bool resetPointers)
 
void setIdentificationP (unsigned int identification)
 
void setIdentificationI (int identification)
 
void setWallInteraction (bool flag)
 
unsigned int getIdentificationP ()
 
int getIdentificationI ()
 
bool isWallInteraction ()
 
virtual bool isBonded () const
 
- Public Member Functions inherited from BaseObject
 BaseObject ()=default
 Default constructor. More...
 
 BaseObject (const BaseObject &p)=default
 Copy constructor, copies all the objects BaseObject contains. More...
 
virtual ~BaseObject ()=default
 virtual destructor More...
 
virtual void moveInHandler (unsigned int index)
 Except that it is virtual, it does the same thing as setIndex() does. More...
 
void setIndex (unsigned int index)
 Allows one to assign an index to an object in the handler/container. More...
 
void setId (unsigned long 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...
 
void setGroupId (unsigned groupId)
 
unsigned getGroupId () const
 

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...
 
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...
 
virtual void reverseHistory ()
 When periodic particles some interaction need certain history properties reversing. This is the function for that. More...
 
void writeInteraction (std::ostream &os, bool created) const
 Writes information about a interaction to the interaction file. More...
 

Detailed Description

Computes normal forces for a Herztian visco-elastic interaction.

Definition at line 39 of file HertzianViscoelasticInteraction.h.

Member Typedef Documentation

Constructor & Destructor Documentation

HertzianViscoelasticInteraction::HertzianViscoelasticInteraction ( BaseInteractable P,
BaseInteractable I,
unsigned  timeStamp 
)

Constructor.

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

Definition at line 40 of file HertzianViscoelasticInteraction.cc.

42  : BaseInteraction(P, I, timeStamp)
43 {
44 #ifdef DEBUG_CONSTRUCTOR
45  std::cout<<"HertzianViscoelasticInteraction::HertzianViscoelasticInteraction() finished"<<std::endl;
46 #endif
47 }
HertzianViscoelasticInteraction::HertzianViscoelasticInteraction ( )
default
HertzianViscoelasticInteraction::HertzianViscoelasticInteraction ( const HertzianViscoelasticInteraction p)

Copy constructor.

Parameters
[in]p

Definition at line 52 of file HertzianViscoelasticInteraction.cc.

53  : BaseInteraction(p)
54 {
55 #ifdef DEBUG_CONSTRUCTOR
56  std::cout<<"HertzianViscoelasticInteraction::HertzianViscoelasticInteraction(const HertzianViscoelasticInteraction& p) finished"<<std::endl;
57 #endif
58 }
HertzianViscoelasticInteraction::~HertzianViscoelasticInteraction ( )
override

Destructor.

Definition at line 65 of file HertzianViscoelasticInteraction.cc.

66 {
67 #ifdef DEBUG_DESTRUCTOR
68  std::cout<<"HertzianViscoelasticInteraction::~HertzianViscoelasticInteraction() finished"<<std::endl;
69 #endif
70 }
HertzianViscoelasticInteraction::HertzianViscoelasticInteraction ( const BaseInteraction p)
inlineexplicit

Definition at line 72 of file HertzianViscoelasticInteraction.h.

72  : BaseInteraction(p)
73  {
74 
75  }

Member Function Documentation

void HertzianViscoelasticInteraction::computeNormalForce ( )

Computes the amount of normal force due to an Hertzian visco-elastic interaction.

The contact model is based on the description given in http://people.ds.cam.ac.uk/jae1001/CUS/research/pfizer/Antypov_Elliott_EPL_2011.pdf (which is the same as in Yade https://answers.launchpad.net/yade/+question/235934) kn = 4/3 E* sqrt(R/2 delta) = sqrt(2)/3 kn fn = kn delta + gamma sqrt(m/2 kn) vn =

Note, the constants are slightly different in the C Thornton model, otherwise it's the same: www.cfd.com.au/cfd_conf12/PDFs/175CUM.pdf

Todo:
check for superquadrics

Definition at line 106 of file HertzianViscoelasticInteraction.cc.

References Vec3D::dot(), BaseInteraction::getContactPoint(), HertzianViscoelasticNormalSpecies::getDissipation(), HertzianViscoelasticNormalSpecies::getEffectiveElasticModulus(), BaseInteraction::getEffectiveMass(), BaseInteraction::getEffectiveRadius(), BaseInteraction::getI(), BaseInteraction::getNormal(), BaseInteraction::getNormalRelativeVelocity(), BaseInteraction::getOverlap(), BaseInteraction::getP(), BaseInteraction::getRelativeVelocity(), getSpecies(), BaseInteraction::setAbsoluteNormalForce(), BaseInteraction::setForce(), BaseInteraction::setNormalRelativeVelocity(), BaseInteraction::setRelativeVelocity(), and BaseInteraction::setTorque().

107 {
108  // This function is called for all particles within interactionRadius distance.
109 
110  // This has to be outside the loop because it is needed for the other forces
111  // Compute the relative velocity vector of particle P w.r.t. I
113  getP()->getVelocityAtContact(getContactPoint()) - getI()->getVelocityAtContact(getContactPoint()));
114  // Compute the projection of vrel onto the normal (can be negative)
116 
117  if (getOverlap() > 0) //if contact forces
118  {
120 
121  Mdouble stiffness = 4. / 3. * species->getEffectiveElasticModulus() * std::sqrt(getEffectiveRadius() * getOverlap());
122 
123  //calculating the current normal force
124  //dissipation is computed such that the restitution is constant
125  Mdouble dissipationCoefficient = species->getDissipation() * sqrt(getEffectiveMass() * stiffness);
126  Mdouble normalForce = stiffness * getOverlap() - dissipationCoefficient * getNormalRelativeVelocity();
127 
128  //setting the normal force parameter in the base interaction class so that it can be accessed
129  //by other classes...
130  setAbsoluteNormalForce(std::abs(normalForce)); //used for further force calculations;
131  setForce(getNormal() * normalForce);
133  setTorque(Vec3D(0.0, 0.0, 0.0));
134  }
135  else
136  {
138  setForce(Vec3D(0.0, 0.0, 0.0));
139  setTorque(Vec3D(0.0, 0.0, 0.0));
140  }
141 }
Mdouble getEffectiveRadius() const
Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) ...
const HertzianViscoelasticNormalSpecies * getSpecies() const
Returns a const pointer of type HerztianViscoelasticNormalSpecies (dynamic-cast). ...
double Mdouble
Definition: GeneralDefine.h:34
const Vec3D & getRelativeVelocity() const
Returns a constant reference to a vector of relative velocity.
void setRelativeVelocity(Vec3D relativeVelocity)
set the relative velocity of the current of the interactions.
void setForce(Vec3D force)
set total force (this is used by the normal force, tangential forces are added use addForce) ...
const Vec3D & getContactPoint() const
Gets constant reference to contact point (vector).
BaseInteractable * getI()
Returns a pointer to the second object involved in the interaction (often a wall or a particle)...
static Mdouble dot(const Vec3D &a, const Vec3D &b)
Calculates the dot product of two Vec3D: .
Definition: Vector.cc:76
void setNormalRelativeVelocity(Mdouble normalRelativeVelocit)
set the normal component of the relative velocity.
const Vec3D & getNormal() const
Gets the normal vector between the two interacting objects.
BaseInteractable * getP()
Returns a pointer to first object involved in the interaction (normally a particle).
Mdouble getNormalRelativeVelocity() const
Returns a double which is the norm (length) of the relative velocity vector.
Mdouble getDissipation() const
Allows the normal dissipation to be accessed.
void setTorque(Vec3D torque)
set the total force (this is used by the normal force, tangential torques are added use addTorque) ...
Mdouble getOverlap() const
Returns a Mdouble with the current overlap between the two interacting objects.
Mdouble getEffectiveElasticModulus() const
Allows the spring constant to be accessed.
void setAbsoluteNormalForce(Mdouble absoluteNormalForce)
the absolute values of the norm (length) of the normal force
Definition: Vector.h:49
HertzianViscoelasticNormalSpecies contains the parameters used to describe a Hertzian normal force (T...
Mdouble getEffectiveMass() const
Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) ...
std::string HertzianViscoelasticInteraction::getBaseName ( ) const

Returns the name of the interaction.

Returns
std::string

Definition at line 91 of file HertzianViscoelasticInteraction.cc.

92 {
93  return "HertzianViscoelastic";
94 }
Mdouble HertzianViscoelasticInteraction::getElasticEnergy ( ) const
overridevirtual

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

kn = 4/3 E* sqrt(R/2 delta) fn = kn delta -> E = int fn ddelta = 2/5 4/3 E sqrt(R/2 delta) delta^2

Reimplemented from BaseInteraction.

Definition at line 148 of file HertzianViscoelasticInteraction.cc.

References HertzianViscoelasticNormalSpecies::getEffectiveElasticModulus(), BaseInteraction::getEffectiveRadius(), BaseInteraction::getOverlap(), getSpecies(), and mathsFunc::square().

149 {
150  if (getOverlap() > 0)
151  {
152  return 8. / 15. * getSpecies()->getEffectiveElasticModulus() * std::sqrt(getEffectiveRadius() * getOverlap()) *
154  }
155  else
156  {
157  return 0.0;
158  }
159 }
Mdouble getEffectiveRadius() const
Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) ...
const HertzianViscoelasticNormalSpecies * getSpecies() const
Returns a const pointer of type HerztianViscoelasticNormalSpecies (dynamic-cast). ...
Mdouble getOverlap() const
Returns a Mdouble with the current overlap between the two interacting objects.
Mdouble getEffectiveElasticModulus() const
Allows the spring constant to be accessed.
T square(const T val)
squares a number
Definition: ExtendedMath.h:104
Mdouble HertzianViscoelasticInteraction::getElasticEnergyAtEquilibrium ( Mdouble  adhesiveForce) const
overridevirtual

Computes elastic-adhesive energy at zero overlap, assuming the energy is zero at the equilibrium point mod = 4/3 E* sqrt(R/2) fn = mod delta^3/2 - fadh -> E = int_deltaEq^0 fn ddelta = [2/5 mod delta^5/2 - fadh * delta]_deltaEq^0 = [2/5 fn delta - 3/5 fadh delta]_deltaEq^0 = 3/5 fadh deltaEq

Todo:
TW consider renaming to getElasticAdhesiveEnergy or getElasticAdhesiveEnergyRelativeToEquilibrium

Reimplemented from BaseInteraction.

Definition at line 176 of file HertzianViscoelasticInteraction.cc.

References HertzianViscoelasticNormalSpecies::getEffectiveElasticModulus(), BaseInteraction::getEffectiveRadius(), getSpecies(), and mathsFunc::square().

177 {
179  const Mdouble modulus = 4. / 3. * species->getEffectiveElasticModulus() * std::sqrt(getEffectiveRadius());
180  const Mdouble equilibriumOverlap = std::cbrt(mathsFunc::square(adhesiveForce / modulus));
181  return 0.6 * adhesiveForce * equilibriumOverlap;//why not 0.4?
182 }
Mdouble getEffectiveRadius() const
Returns a Mdouble to the effective radius of the interaction. (Not corrected for the overlap) ...
const HertzianViscoelasticNormalSpecies * getSpecies() const
Returns a const pointer of type HerztianViscoelasticNormalSpecies (dynamic-cast). ...
double Mdouble
Definition: GeneralDefine.h:34
Mdouble getEffectiveElasticModulus() const
Allows the spring constant to be accessed.
T square(const T val)
squares a number
Definition: ExtendedMath.h:104
HertzianViscoelasticNormalSpecies contains the parameters used to describe a Hertzian normal force (T...
const HertzianViscoelasticNormalSpecies * HertzianViscoelasticInteraction::getSpecies ( ) const

Returns a const pointer of type HerztianViscoelasticNormalSpecies (dynamic-cast).

Returns
const HertzianViscoelasticNormalSpecies*

Definition at line 164 of file HertzianViscoelasticInteraction.cc.

References BaseInteraction::getBaseSpecies(), and BaseSpecies::getNormalForce().

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

165 {
166  return static_cast<const HertzianViscoelasticNormalSpecies*>(getBaseSpecies()->getNormalForce());
167 }
BaseNormalForce * getNormalForce() const
Definition: BaseSpecies.h:148
const BaseSpecies * getBaseSpecies() const
Return a constant point to BaseSpecies of the interaction.
HertzianViscoelasticNormalSpecies contains the parameters used to describe a Hertzian normal force (T...
void HertzianViscoelasticInteraction::read ( std::istream &  is)
overridevirtual

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

Parameters
[in,out]is

Reimplemented from BaseInteraction.

Definition at line 83 of file HertzianViscoelasticInteraction.cc.

References BaseInteraction::read().

84 {
86 }
void read(std::istream &is) override
Interaction read function, which accepts an std::istream as input.
void HertzianViscoelasticInteraction::write ( std::ostream &  os) const
overridevirtual

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

Parameters
[in,out]os

Reimplemented from BaseInteraction.

Definition at line 75 of file HertzianViscoelasticInteraction.cc.

References BaseInteraction::write().

76 {
78 }
void write(std::ostream &os) const override
Interaction print function, which accepts an std::ostream as input.

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