rigidBodyInertia.H

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License
    This file is part of OpenFOAM.
 
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    the Free Software Foundation, either version 3 of the License, or
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Class
    Foam::RBD::rigidBodyInertia
 
Description
    This class represents the linear and angular inertia of a rigid body
    by the mass, centre of mass and moment of inertia tensor about the
    centre of mass.
 
    Reference:
    \verbatim
        Featherstone, R. (2008).
        Rigid body dynamics algorithms.
        Springer.
    \endverbatim
 
SourceFiles
    rigidBodyInertiaI.H
    rigidBodyInertia.C
    rigidBodyInertiaIO.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef RBD_rigidBodyInertia_H
#define RBD_rigidBodyInertia_H
 
#include "vector.H"
#include "symmTensor.H"
#include "spatialVector.H"
#include "spatialTensor.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
// Forward declaration of classes
class Istream;
class Ostream;
 
namespace RBD
{
 
// Forward declaration of friend functions and operators
class rigidBodyInertia;
Istream& operator>>(Istream&, rigidBodyInertia&);
Ostream& operator<<(Ostream&, const rigidBodyInertia&);
 
 
/*---------------------------------------------------------------------------*\
                      Class rigidBodyInertia Declaration
\*---------------------------------------------------------------------------*/
 
class rigidBodyInertia
{
    // Private Data
 
        //- Mass of the rigid-body
        scalar m_;
 
        //- Centre of mass of the rigid-body
        vector c_;
 
        //- Inertia tensor about the centre of mass
        symmTensor Ic_;
 
 
public:
 
    // Static member functions
 
        //- Return the difference between the inertia tensor of the rigid-body
        //  about the origin - about the centre of mass
        //  for the given mass and centre of mass
        inline static symmTensor Ioc(const scalar m, const vector& c);
 
 
    // Constructors
 
        //- Null constructor, initialises to zero
        inline rigidBodyInertia();
 
        //- Construct from mass, centre of mass and moment of inertia tensor
        //  about the centre of mass
        inline rigidBodyInertia
        (
            const scalar m,
            const vector& c,
            const symmTensor& Ic
        );
 
        //- Construct from dictionary
        inline rigidBodyInertia(const dictionary& dict);
 
        //- Construct from the components of a spatial tensor
        inline explicit rigidBodyInertia(const spatialTensor& st);
 
        //- Construct from Istream
        inline explicit rigidBodyInertia(Istream& is);
 
 
    // Member Functions
 
        //- Return the mass of the rigid-body
        inline scalar m() const;
 
        //- Return the centre of mass of the rigid-body
        inline const vector& c() const;
 
        //- Return the inertia tensor of the rigid-body about the centre of mass
        inline const symmTensor& Ic() const;
 
        //- Return the difference between the inertia tensor of the rigid-body
        //  about the origin - about the centre of mass
        inline symmTensor Ioc() const;
 
        //- Return the difference between the inertia tensor of the rigid-body
        //  about the a new centre of mass - about the current centre of mass
        inline symmTensor Icc(const vector& c) const;
 
        //- Return the inertia tensor of the rigid-body about the origin
        inline symmTensor Io() const;
 
        //- Return the kinetic energy of the body with the given velocity
        inline scalar kineticEnergy(const spatialVector& v);
 
 
    // Member Operators
 
        //- Conversion to spatial tensor
        inline operator spatialTensor() const;
 
        inline void operator+=(const rigidBodyInertia&);
 
 
    // IOstream Operators
 
        friend Istream& operator>>(Istream&, rigidBodyInertia&);
        friend Ostream& operator<<(Ostream&, const rigidBodyInertia&);
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace RBD
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#include "rigidBodyInertiaI.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //