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========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Copyright (C) 2016-2024 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
\*---------------------------------------------------------------------------*/
#include "linearSpring.H"
#include "rigidBodyModel.H"
#include "addToRunTimeSelectionTable.H"
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
namespace Foam
{
namespace RBD
{
namespace restraints
{
defineTypeNameAndDebug(linearSpring, 0);
addToRunTimeSelectionTable
(
restraint,
linearSpring,
dictionary
);
}
}
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::RBD::restraints::linearSpring::linearSpring
(
const word& name,
const dictionary& dict,
const rigidBodyModel& model
)
:
restraint(name, dict, model)
{
read(dict);
}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
Foam::RBD::restraints::linearSpring::~linearSpring()
{}
// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
void Foam::RBD::restraints::linearSpring::restrain
(
scalarField& tau,
Field<spatialVector>& fx,
const rigidBodyModelState& state
) const
{
point attachmentPt = bodyPoint(refAttachmentPt_);
// Current axis of the spring
vector r = attachmentPt - anchor_;
scalar magR = mag(r);
r /= (magR + vSmall);
// Velocity of the attached end of the spring
vector v = bodyPointVelocity(refAttachmentPt_).l();
// Force and moment on the master body including optional damping
vector force
(
(allowSlack_ && magR < restLength_)
? -damping_*(r & v)*r
: (-stiffness_*(magR - restLength_) - damping_*(r & v))*r
);
vector moment(attachmentPt ^ force);
if (model_.debug)
{
Info<< " attachmentPt " << attachmentPt
<< " attachmentPt - anchor " << r*magR
<< " spring length " << magR
<< " allow slack " << allowSlack_
<< " force " << force
<< " moment " << moment
<< endl;
}
// Accumulate the force for the restrained body
fx[masterBodyIndex_] += spatialVector(moment, force);
}
bool Foam::RBD::restraints::linearSpring::read
(
const dictionary& dict
)
{
restraint::read(dict);
coeffs_.lookup("anchor") >> anchor_;
coeffs_.lookup("refAttachmentPt") >> refAttachmentPt_;
coeffs_.lookup("stiffness") >> stiffness_;
coeffs_.lookup("damping") >> damping_;
coeffs_.lookup("restLength") >> restLength_;
allowSlack_ = coeffs_.lookupOrDefault<Switch>("allowSlack", false);
return true;
}
void Foam::RBD::restraints::linearSpring::write
(
Ostream& os
) const
{
restraint::write(os);
writeEntry(os, "anchor", anchor_);
writeEntry(os, "refAttachmentPt", refAttachmentPt_);
writeEntry(os, "stiffness", stiffness_);
writeEntry(os, "damping", damping_);
writeEntry(os, "restLength", restLength_);
writeEntry(os, "allowSlack", allowSlack_);
}
// ************************************************************************* //
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