Commit 46cd2b3b authored by Henry Weller's avatar Henry Weller
Browse files

rigidBodyDynamics/restraints: Added linearAxialAngularSpring, linear axial angular spring restraint

Included for backward-compatibility with the 6-DoF solver but in the
future will be re-implemented as a joint rather than body restraint and
accumulated in tau (internal forces) rather than fx (external forces).
parent 3d5410d2
......@@ -29,6 +29,7 @@ restraints/restraint/rigidBodyRestraint.C
restraints/restraint/rigidBodyRestraintNew.C
restraints/linearSpring/linearSpring.C
restraints/linearDamper/linearDamper.C
restraints/linearAxialAngularSpring/linearAxialAngularSpring.C
rigidBodyModel/rigidBodyModel.C
rigidBodyModel/forwardDynamics.C
......
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 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 "linearAxialAngularSpring.H"
#include "rigidBodyModel.H"
#include "addToRunTimeSelectionTable.H"
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
namespace Foam
{
namespace RBD
{
namespace restraints
{
defineTypeNameAndDebug(linearAxialAngularSpring, 0);
addToRunTimeSelectionTable
(
restraint,
linearAxialAngularSpring,
dictionary
);
}
}
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::RBD::restraints::linearAxialAngularSpring::
linearAxialAngularSpring
(
const word& name,
const dictionary& dict,
const rigidBodyModel& model
)
:
restraint(name, dict, model)
{
read(dict);
}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
Foam::RBD::restraints::linearAxialAngularSpring::
~linearAxialAngularSpring()
{}
// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
Foam::spatialVector
Foam::RBD::restraints::linearAxialAngularSpring::restrain() const
{
vector refDir = rotationTensor(vector(1, 0, 0), axis_) & vector(0, 1, 0);
vector oldDir = refQ_ & refDir;
vector newDir = model_.X0(bodyID_).E() & refDir;
if (mag(oldDir & axis_) > 0.95 || mag(newDir & axis_) > 0.95)
{
// Directions close to the axis, changing reference
refDir = rotationTensor(vector(1, 0, 0), axis_) & vector(0, 0, 1);
oldDir = refQ_ & refDir;
newDir = model_.X0(bodyID_).E() & refDir;
}
// Removing axis component from oldDir and newDir and normalising
oldDir -= (axis_ & oldDir)*axis_;
oldDir /= (mag(oldDir) + VSMALL);
newDir -= (axis_ & newDir)*axis_;
newDir /= (mag(newDir) + VSMALL);
scalar theta = mag(acos(min(oldDir & newDir, 1.0)));
// Temporary axis with sign information
vector a = (oldDir ^ newDir);
// Ensure a is in direction of axis
a = (a & axis_)*axis_;
scalar magA = mag(a);
if (magA > VSMALL)
{
a /= magA;
}
else
{
a = Zero;
}
// Damping of along axis angular velocity only
vector moment
(
-(
stiffness_*theta
+ damping_*(model_.v(model_.master(bodyID_)).w() & a)
)*a
);
if (model_.debug)
{
Info<< " angle " << theta*sign(a & axis_)
<< " moment " << moment
<< endl;
}
return spatialVector(moment, Zero);
}
bool Foam::RBD::restraints::linearAxialAngularSpring::read
(
const dictionary& dict
)
{
restraint::read(dict);
refQ_ = coeffs_.lookupOrDefault<tensor>("referenceOrientation", I);
if (mag(mag(refQ_) - sqrt(3.0)) > 1e-9)
{
FatalErrorInFunction
<< "referenceOrientation " << refQ_ << " is not a rotation tensor. "
<< "mag(referenceOrientation) - sqrt(3) = "
<< mag(refQ_) - sqrt(3.0) << nl
<< exit(FatalError);
}
axis_ = coeffs_.lookup("axis");
scalar magAxis(mag(axis_));
if (magAxis > VSMALL)
{
axis_ /= magAxis;
}
else
{
FatalErrorInFunction
<< "axis has zero length"
<< abort(FatalError);
}
coeffs_.lookup("stiffness") >> stiffness_;
coeffs_.lookup("damping") >> damping_;
return true;
}
void Foam::RBD::restraints::linearAxialAngularSpring::write
(
Ostream& os
) const
{
restraint::write(os);
os.writeKeyword("referenceOrientation")
<< refQ_ << token::END_STATEMENT << nl;
os.writeKeyword("axis")
<< axis_ << token::END_STATEMENT << nl;
os.writeKeyword("stiffness")
<< stiffness_ << token::END_STATEMENT << nl;
os.writeKeyword("damping")
<< damping_ << token::END_STATEMENT << nl;
}
// ************************************************************************* //
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 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/>.
Class
Foam::RBD::restraints::linearAxialAngularSpring
Description
Linear axial angular spring restraint.
SourceFiles
linearAxialAngularSpring.C
\*---------------------------------------------------------------------------*/
#ifndef linearAxialAngularSpring_H
#define linearAxialAngularSpring_H
#include "rigidBodyRestraint.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace RBD
{
namespace restraints
{
/*---------------------------------------------------------------------------*\
Class linearAxialAngularSpring Declaration
\*---------------------------------------------------------------------------*/
class linearAxialAngularSpring
:
public restraint
{
// Private data
//- Reference orientation where there is no moment
tensor refQ_;
//- Global unit axis around which the motion is sprung
vector axis_;
//- Spring stiffness coefficient (Nm/rad)
scalar stiffness_;
//- Damping coefficient (Nms/rad)
scalar damping_;
public:
//- Runtime type information
TypeName("linearAxialAngularSpring");
// Constructors
//- Construct from components
linearAxialAngularSpring
(
const word& name,
const dictionary& dict,
const rigidBodyModel& model
);
//- Construct and return a clone
virtual autoPtr<restraint> clone() const
{
return autoPtr<restraint>
(
new linearAxialAngularSpring(*this)
);
}
//- Destructor
virtual ~linearAxialAngularSpring();
// Member Functions
//- Return the external force applied to the body by this restraint
virtual spatialVector restrain() const;
//- Update properties from given dictionary
virtual bool read(const dictionary& dict);
//- Write
virtual void write(Ostream&) const;
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace RBD
} // End namespace RBD
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //
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