LinearViscoelasticNormalSpecies.cc

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#include "LinearViscoelasticNormalSpecies.h"
#include "Interactions/BaseInteraction.h"
#include<cmath>
#include <Interactions/NormalForceInteractions/LinearViscoelasticInteraction.h>
#include "Logger.h"

class BaseParticle;
class BaseInteractable;

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

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

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

void LinearViscoelasticNormalSpecies::write(std::ostream& os) const
{
    os << " stiffness " << stiffness_
            << " dissipation " << dissipation_;
}

void LinearViscoelasticNormalSpecies::read(std::istream& is)
{
    std::string dummy;
    is >> dummy >> stiffness_
            >> dummy >> dissipation_;
}

std::string LinearViscoelasticNormalSpecies::getBaseName() const
{
    return "LinearViscoelastic";
}

void LinearViscoelasticNormalSpecies::setStiffness(Mdouble new_k)
{
    if (new_k >= 0)
        stiffness_ = new_k;
    else
    {
        std::cerr << "Error in set_k" << std::endl;
        exit(-1);
    }
}

Mdouble LinearViscoelasticNormalSpecies::getStiffness() const
{
    return stiffness_;
}

void LinearViscoelasticNormalSpecies::setStiffnessAndDissipation(helpers::KAndDisp new_)
{
    setStiffness(new_.k);
    setDissipation(new_.disp);
}

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

Mdouble LinearViscoelasticNormalSpecies::getDissipation() const
{
    return dissipation_;
}

Mdouble LinearViscoelasticNormalSpecies::getCollisionTime(Mdouble mass) const
{
    if (mass <= 0)
    {
        std::cerr << "Warning in getCollisionTime(" << mass << ") mass is not set or has an unexpected value, (getCollisionTime(" << mass << "))" << std::endl;
    }
    if (stiffness_ <= 0)
    {
        std::cerr << "Warning in getCollisionTime(" << mass << ") stiffness=" << stiffness_ << " is not set or has an unexpected value, (getCollisionTime(" << mass << "), with stiffness=" << stiffness_ << ")" << std::endl;
    }
    if (dissipation_ < 0)
    {
        std::cerr << "Warning in getCollisionTime(" << mass << ") dissipation=" << dissipation_ << " is not set or has an unexpected value, (getCollisionTime(" << mass << "), with dissipation=" << dissipation_ << ")" << std::endl;
    }
    Mdouble tosqrt = stiffness_ / (.5 * mass) - mathsFunc::square(dissipation_ / mass);
    if (tosqrt <= 0)
    {
        std::cerr << "Warning in getCollisionTime(" << mass << ") values for mass, stiffness and dissipation would lead to an overdamped system, (getCollisionTime(" << mass << "), with stiffness=" << stiffness_ << " and dissipation=" << dissipation_ << ")" << std::endl;
    }
    return constants::pi / std::sqrt(tosqrt);
}

Mdouble LinearViscoelasticNormalSpecies::getRestitutionCoefficient(Mdouble mass) const
{
    return std::exp(-dissipation_ / mass * getCollisionTime(mass));
}

Mdouble LinearViscoelasticNormalSpecies::getMaximumVelocity(Mdouble radius, Mdouble mass) const
{
    return radius * std::sqrt(stiffness_ / (.5 * mass));
}

void LinearViscoelasticNormalSpecies::setStiffnessAndRestitutionCoefficient(Mdouble stiffness, Mdouble eps, Mdouble mass)
{
    stiffness_ = stiffness;
    if (eps==0.0) {
        dissipation_ = std::sqrt(2.0 * mass * stiffness);
    } else {
        dissipation_ = -std::sqrt(2.0 * mass * stiffness / (constants::sqr_pi + mathsFunc::square(log(eps)))) * log(eps);
    }
}

void LinearViscoelasticNormalSpecies::setCollisionTimeAndRestitutionCoefficient(Mdouble tc, Mdouble eps, Mdouble mass)
{
    if (eps==0.0) {
        stiffness_ = .5 * mass * mathsFunc::square(constants::pi / tc);
        dissipation_ = std::sqrt(2.0 * mass * stiffness_);
    } else {
        dissipation_ = -mass / tc * mathsFunc::log(eps);
        stiffness_ = .5 * mass * (mathsFunc::square(constants::pi / tc) 
            + mathsFunc::square(dissipation_ / mass));
    }
    logger(INFO,"setCollisionTimeAndRestitutionCoefficient: set stiffness to % and dissipation to % to obtain a collision time of % and a restitution coefficient of % for two particles of mass %",
           getStiffness(),getDissipation(),tc,eps,mass);
}

void LinearViscoelasticNormalSpecies::setCollisionTimeAndRestitutionCoefficient(Mdouble collisionTime, Mdouble restitutionCoefficient, Mdouble mass1, Mdouble mass2)
{
    Mdouble reduced_mass = mass1 * mass2 / (mass1 + mass2);
    setCollisionTimeAndRestitutionCoefficient(collisionTime, restitutionCoefficient, 2.0 * reduced_mass);
}

void LinearViscoelasticNormalSpecies::mix(LinearViscoelasticNormalSpecies* const S, LinearViscoelasticNormalSpecies* const T)
{
    stiffness_ = average(S->getStiffness(), T->getStiffness());
    dissipation_ = average(S->getDissipation(), T->getDissipation());
}