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/////////////////////////////////////////////////////////////
// //
// Copyright (c) 2003-2014 by The University of Queensland //
// Centre for Geoscience Computing //
// http://earth.uq.edu.au/centre-geoscience-computing //
// //
// Primary Business: Brisbane, Queensland, Australia //
// Licensed under the Open Software License version 3.0 //
// http://www.apache.org/licenses/LICENSE-2.0 //
// //
/////////////////////////////////////////////////////////////
/*
HertzianViscoElasticInteraction.cpp:
Written by Laura Heredia and Pablo Richeri, 2009.
*/
#include "HertzianViscoElasticInteraction.h"
// --- system includes ---
#include <iostream>
// --- member functions for interaction group parameter class ---
//! default constructor
CHertzianViscoElasticIGP::CHertzianViscoElasticIGP()
: AIGParam(), m_A(0.0), m_E(0.0), m_nu(0.0)
{
}
/*!
constructor with parameters
\param name the name of the interaction group
\param k the stiffness constant
*/
CHertzianViscoElasticIGP::CHertzianViscoElasticIGP(
const std::string& name,
double A,
double E,
double nu
)
: AIGParam(name), m_A(A), m_E(E), m_nu(nu)
{
}
// --- function of interaction class ---
CHertzianViscoElasticInteraction::CHertzianViscoElasticInteraction(
CParticle* p1,
CParticle* p2,
const CHertzianViscoElasticIGP& param
)
: APairInteraction(p1,p2)
{
m_A=param.m_A;
m_E=param.m_E;
m_nu=param.m_nu;
m_force=Vec3(0.0,0.0,0.0);
m_dn=0.0;
}
/*!
calculate forces
*/
void CHertzianViscoElasticInteraction::calcForces()
{
Vec3 D=m_p1->getPos()-m_p2->getPos();
double dist=D*D;
double eq_dist=m_p1->getRad()+m_p2->getRad();
//std::cerr << "d: " << dist << " / " << eq_dist*eq_dist << std::endl;
if(dist<(eq_dist*eq_dist)){
double R_ij=1.0/(1.0/m_p1->getRad()+1.0/m_p2->getRad());
dist=sqrt(dist);
m_dn=eq_dist-dist;
Vec3 dir=D.unit();
//Calculate d m_dn / dt
double ex=D.X()/dist;
double ey=D.Y()/dist;
double ez=D.Z()/dist;
double dvx=m_p1->getVel().X()-m_p2->getVel().X();
double dvy=m_p1->getVel().Y()-m_p2->getVel().Y();
double dvz=m_p1->getVel().Z()-m_p2->getVel().Z();
double m_dn_dot=-(ex*dvx+ey*dvy+ez*dvz);
double norm_m_force =
(2.0*m_E*sqrt(R_ij)) /
(3.0*(1.0-m_nu*m_nu)) *
(pow(m_dn,1.5)+m_A*sqrt(m_dn)*m_dn_dot);
m_force=norm_m_force<0?Vec3(0.0,0.0,0.0):dir*norm_m_force;
//std::cerr << "HF: " << dir << " " << R_ij << " " << m_dn << " "
// << m_force << std::endl;
Vec3 pos=m_p2->getPos()+(m_p2->getRad()/eq_dist)*D;
m_p1->applyForce(m_force,pos);
m_p2->applyForce(-1.0*m_force,pos);
} else {
m_force=Vec3(0.0,0.0,0.0);
m_dn=0.0;
}
}
/*!
"field function" returning force currently exerted by interaction
*/
Vec3 CHertzianViscoElasticInteraction::getForce() const
{
return m_force;
}
/*!
"field function" returning potential energy currently stored in interaction
*/
double CHertzianViscoElasticInteraction::getPotentialEnergy() const
{
return 0.4*m_force.norm()*m_dn;
}
/*!
Get the particle member function which returns a scalar field of a given name.
\param name the name of the field
*/
CHertzianViscoElasticInteraction::ScalarFieldFunction
CHertzianViscoElasticInteraction::getScalarFieldFunction(const string& name)
{
CHertzianViscoElasticInteraction::ScalarFieldFunction sf;
if (name=="potential_energy"){
sf=&CHertzianViscoElasticInteraction::getPotentialEnergy;
} else if (name=="count"){
sf=&CHertzianViscoElasticInteraction::Count;
} else {
sf=NULL;
std::cerr
<< "ERROR - invalid name for interaction scalar access function"
<< std::endl;
}
return sf;
}
/*!
Get the particle member function which returns a vector field of a given name.
\param name the name of the field
*/
CHertzianViscoElasticInteraction::VectorFieldFunction
CHertzianViscoElasticInteraction::getVectorFieldFunction(const string& name)
{
CHertzianViscoElasticInteraction::VectorFieldFunction vf;
if (name=="force"){
vf=&CHertzianViscoElasticInteraction::getForce;
} else {
vf=NULL;
cerr
<< "ERROR - invalid name for interaction vector access function"
<< endl;
}
return vf;
}
/*!
dummy
*/
CHertzianViscoElasticInteraction::CheckedScalarFieldFunction
CHertzianViscoElasticInteraction::getCheckedScalarFieldFunction(
const string& name
)
{
CHertzianViscoElasticInteraction::CheckedScalarFieldFunction csf;
csf=NULL;
cerr
<< "ERROR - invalid name for interaction vector access function"
<< endl;
return csf;
}
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