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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 //
// //
/////////////////////////////////////////////////////////////
#include "HertzianElasticInteraction.h"
// --- system includes ---
#include <iostream>
// --- member functions for interaction group parameter class ---
//! default constructor
CHertzianElasticIGP::CHertzianElasticIGP(): AIGParam(), m_E(0.0), m_nu(0.0)
{}
/*!
constructor with parameters
\param name the name of the interaction group
\param k the stiffness constant
*/
CHertzianElasticIGP::CHertzianElasticIGP(const std::string& name,double E,double nu)
: AIGParam(name), m_E(E), m_nu(nu)
{}
// --- function of interaction class ---
CHertzianElasticInteraction::CHertzianElasticInteraction(CParticle* p1,CParticle* p2, const CHertzianElasticIGP& param) : APairInteraction(p1,p2)
{
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 CHertzianElasticInteraction::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();
m_force=dir*(m_E*sqrt(R_ij))/(2.0*(1.0-m_nu*m_nu))*pow(m_dn,1.5);
//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 CHertzianElasticInteraction::getForce() const
{
return m_force;
}
/*!
"field function" returning potential energy currently stored in interaction
*/
double CHertzianElasticInteraction::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
*/
CHertzianElasticInteraction::ScalarFieldFunction CHertzianElasticInteraction::getScalarFieldFunction(const string& name)
{
CHertzianElasticInteraction::ScalarFieldFunction sf;
if (name=="potential_energy"){
sf=&CHertzianElasticInteraction::getPotentialEnergy;
} else if (name=="count"){
sf=&CHertzianElasticInteraction::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
*/
CHertzianElasticInteraction::VectorFieldFunction CHertzianElasticInteraction::getVectorFieldFunction(const string& name)
{
CHertzianElasticInteraction::VectorFieldFunction vf;
if (name=="force"){
vf=&CHertzianElasticInteraction::getForce;
} else {
vf=NULL;
cerr << "ERROR - invalid name for interaction vector access function" << endl;
}
return vf;
}
/*!
dummy
*/
CHertzianElasticInteraction::CheckedScalarFieldFunction CHertzianElasticInteraction::getCheckedScalarFieldFunction(const string& name)
{
CHertzianElasticInteraction::CheckedScalarFieldFunction csf;
csf=NULL;
cerr << "ERROR - invalid name for interaction vector access function" << endl;
return csf;
}
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