linearSpring.C

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    Copyright (C) 2011-2016 OpenFOAM Foundation
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
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    under the terms of the GNU General Public License as published by
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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#include "linearSpring.H"
#include "addToRunTimeSelectionTable.H"
#include "sixDoFRigidBodyMotion.H"
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
namespace Foam
{
namespace sixDoFRigidBodyMotionRestraints
{
    defineTypeNameAndDebug(linearSpring, 0);
 
    addToRunTimeSelectionTable
    (
        sixDoFRigidBodyMotionRestraint,
        linearSpring,
        dictionary
    );
}
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
Foam::sixDoFRigidBodyMotionRestraints::linearSpring::linearSpring
(
    const word& name,
    const dictionary& sDoFRBMRDict
)
:
    sixDoFRigidBodyMotionRestraint(name, sDoFRBMRDict),
    anchor_(),
    refAttachmentPt_(),
    stiffness_(),
    damping_(),
    restLength_()
{
    read(sDoFRBMRDict);
}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
Foam::sixDoFRigidBodyMotionRestraints::linearSpring::~linearSpring()
{}
 
 
// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
 
void Foam::sixDoFRigidBodyMotionRestraints::linearSpring::restrain
(
    const sixDoFRigidBodyMotion& motion,
    vector& restraintPosition,
    vector& restraintForce,
    vector& restraintMoment
) const
{
    restraintPosition = motion.transform(refAttachmentPt_);
 
    vector r = restraintPosition - anchor_;
 
    scalar magR = mag(r);
    r /= (magR + VSMALL);
 
    vector v = motion.velocity(restraintPosition);
 
    restraintForce = -stiffness_*(magR - restLength_)*r - damping_*(r & v)*r;
 
    restraintMoment = Zero;
 
    if (motion.report())
    {
        Info<< " attachmentPt - anchor " << r*magR
            << " spring length " << magR
            << " force " << restraintForce
            << endl;
    }
}
 
 
bool Foam::sixDoFRigidBodyMotionRestraints::linearSpring::read
(
    const dictionary& sDoFRBMRDict
)
{
    sixDoFRigidBodyMotionRestraint::read(sDoFRBMRDict);
 
    sDoFRBMRCoeffs_.readEntry("anchor", anchor_);
    sDoFRBMRCoeffs_.readEntry("refAttachmentPt", refAttachmentPt_);
    sDoFRBMRCoeffs_.readEntry("stiffness", stiffness_);
    sDoFRBMRCoeffs_.readEntry("damping", damping_);
    sDoFRBMRCoeffs_.readEntry("restLength", restLength_);
 
    return true;
}
 
 
void Foam::sixDoFRigidBodyMotionRestraints::linearSpring::write
(
    Ostream& os
) const
{
    os.writeEntry("anchor", anchor_);
    os.writeEntry("refAttachmentPt", refAttachmentPt_);
    os.writeEntry("stiffness", stiffness_);
    os.writeEntry("damping", damping_);
    os.writeEntry("restLength", restLength_);
}
 
// ************************************************************************* //