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).
This commit is contained in:
Henry Weller
@ -29,6 +29,7 @@ restraints/restraint/rigidBodyRestraint.C
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restraints/restraint/rigidBodyRestraintNew.C
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restraints/linearSpring/linearSpring.C
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restraints/linearDamper/linearDamper.C
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restraints/linearAxialAngularSpring/linearAxialAngularSpring.C
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rigidBodyModel/rigidBodyModel.C
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rigidBodyModel/forwardDynamics.C
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@ -0,0 +1,199 @@
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/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration |
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\\ / A nd | Copyright (C) 2016 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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\*---------------------------------------------------------------------------*/
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#include "linearAxialAngularSpring.H"
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#include "rigidBodyModel.H"
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#include "addToRunTimeSelectionTable.H"
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// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
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namespace Foam
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{
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namespace RBD
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{
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namespace restraints
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{
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defineTypeNameAndDebug(linearAxialAngularSpring, 0);
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addToRunTimeSelectionTable
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(
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restraint,
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linearAxialAngularSpring,
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dictionary
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);
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}
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}
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}
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// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
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Foam::RBD::restraints::linearAxialAngularSpring::
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linearAxialAngularSpring
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(
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const word& name,
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const dictionary& dict,
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const rigidBodyModel& model
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)
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:
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restraint(name, dict, model)
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{
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read(dict);
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}
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// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
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Foam::RBD::restraints::linearAxialAngularSpring::
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~linearAxialAngularSpring()
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{}
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// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
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Foam::spatialVector
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Foam::RBD::restraints::linearAxialAngularSpring::restrain() const
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{
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vector refDir = rotationTensor(vector(1, 0, 0), axis_) & vector(0, 1, 0);
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vector oldDir = refQ_ & refDir;
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vector newDir = model_.X0(bodyID_).E() & refDir;
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if (mag(oldDir & axis_) > 0.95 || mag(newDir & axis_) > 0.95)
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{
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// Directions close to the axis, changing reference
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refDir = rotationTensor(vector(1, 0, 0), axis_) & vector(0, 0, 1);
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oldDir = refQ_ & refDir;
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newDir = model_.X0(bodyID_).E() & refDir;
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}
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// Removing axis component from oldDir and newDir and normalising
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oldDir -= (axis_ & oldDir)*axis_;
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oldDir /= (mag(oldDir) + VSMALL);
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newDir -= (axis_ & newDir)*axis_;
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newDir /= (mag(newDir) + VSMALL);
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scalar theta = mag(acos(min(oldDir & newDir, 1.0)));
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// Temporary axis with sign information
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vector a = (oldDir ^ newDir);
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// Ensure a is in direction of axis
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a = (a & axis_)*axis_;
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scalar magA = mag(a);
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if (magA > VSMALL)
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{
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a /= magA;
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}
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else
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{
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a = Zero;
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}
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// Damping of along axis angular velocity only
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vector moment
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(
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-(
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stiffness_*theta
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+ damping_*(model_.v(model_.master(bodyID_)).w() & a)
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)*a
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);
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if (model_.debug)
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{
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Info<< " angle " << theta*sign(a & axis_)
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<< " moment " << moment
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<< endl;
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}
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return spatialVector(moment, Zero);
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}
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bool Foam::RBD::restraints::linearAxialAngularSpring::read
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(
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const dictionary& dict
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)
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{
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restraint::read(dict);
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refQ_ = coeffs_.lookupOrDefault<tensor>("referenceOrientation", I);
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if (mag(mag(refQ_) - sqrt(3.0)) > 1e-9)
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{
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FatalErrorInFunction
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<< "referenceOrientation " << refQ_ << " is not a rotation tensor. "
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<< "mag(referenceOrientation) - sqrt(3) = "
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<< mag(refQ_) - sqrt(3.0) << nl
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<< exit(FatalError);
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}
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axis_ = coeffs_.lookup("axis");
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scalar magAxis(mag(axis_));
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if (magAxis > VSMALL)
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{
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axis_ /= magAxis;
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}
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else
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{
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FatalErrorInFunction
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<< "axis has zero length"
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<< abort(FatalError);
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}
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coeffs_.lookup("stiffness") >> stiffness_;
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coeffs_.lookup("damping") >> damping_;
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return true;
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}
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void Foam::RBD::restraints::linearAxialAngularSpring::write
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(
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Ostream& os
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) const
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{
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restraint::write(os);
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os.writeKeyword("referenceOrientation")
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<< refQ_ << token::END_STATEMENT << nl;
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os.writeKeyword("axis")
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<< axis_ << token::END_STATEMENT << nl;
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os.writeKeyword("stiffness")
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<< stiffness_ << token::END_STATEMENT << nl;
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os.writeKeyword("damping")
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<< damping_ << token::END_STATEMENT << nl;
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}
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// ************************************************************************* //
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@ -0,0 +1,125 @@
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/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration |
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\\ / A nd | Copyright (C) 2016 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
|
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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
|
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(at your option) any later version.
|
||||
|
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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.
|
||||
|
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You should have received a copy of the GNU General Public License
|
||||
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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Class
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Foam::RBD::restraints::linearAxialAngularSpring
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Description
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Linear axial angular spring restraint.
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SourceFiles
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linearAxialAngularSpring.C
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\*---------------------------------------------------------------------------*/
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#ifndef linearAxialAngularSpring_H
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#define linearAxialAngularSpring_H
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#include "rigidBodyRestraint.H"
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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namespace Foam
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{
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namespace RBD
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{
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namespace restraints
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{
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/*---------------------------------------------------------------------------*\
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Class linearAxialAngularSpring Declaration
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\*---------------------------------------------------------------------------*/
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class linearAxialAngularSpring
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:
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public restraint
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{
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// Private data
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//- Reference orientation where there is no moment
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tensor refQ_;
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//- Global unit axis around which the motion is sprung
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vector axis_;
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//- Spring stiffness coefficient (Nm/rad)
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scalar stiffness_;
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//- Damping coefficient (Nms/rad)
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scalar damping_;
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public:
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//- Runtime type information
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TypeName("linearAxialAngularSpring");
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// Constructors
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//- Construct from components
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linearAxialAngularSpring
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(
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const word& name,
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const dictionary& dict,
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const rigidBodyModel& model
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);
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//- Construct and return a clone
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virtual autoPtr<restraint> clone() const
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{
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return autoPtr<restraint>
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(
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new linearAxialAngularSpring(*this)
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);
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}
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//- Destructor
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virtual ~linearAxialAngularSpring();
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// Member Functions
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//- Return the external force applied to the body by this restraint
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virtual spatialVector restrain() const;
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//- Update properties from given dictionary
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virtual bool read(const dictionary& dict);
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//- Write
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virtual void write(Ostream&) const;
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};
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace RBD
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} // End namespace RBD
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} // End namespace Foam
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#endif
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// ************************************************************************* //
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Reference in New Issue
Block a user