/*---------------------------------------------------------------------------*\
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    \\  /    A nd           | Copyright (C) 2011-2018 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/>.

Application
    solidDisplacementFoam

Description
    Transient segregated finite-volume solver of linear-elastic,
    small-strain deformation of a solid body, with optional thermal
    diffusion and thermal stresses.

    Simple linear elasticity structural analysis code.
    Solves for the displacement vector field D, also generating the
    stress tensor field sigma.

\*---------------------------------------------------------------------------*/

#include "fvCFD.H"
#include "fvOptions.H"
#include "Switch.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

int main(int argc, char *argv[])
{
    #include "postProcess.H"

    #include "setRootCaseLists.H"
    #include "createTime.H"
    #include "createMesh.H"
    #include "createControls.H"
    #include "createFields.H"

    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    Info<< "\nCalculating displacement field\n" << endl;

    while (runTime.loop())
    {
        Info<< "Iteration: " << runTime.value() << nl << endl;

        #include "readSolidDisplacementFoamControls.H"

        int iCorr = 0;
        scalar initialResidual = 0;

        do
        {
            if (thermalStress)
            {
                volScalarField& T = Tptr();
                fvScalarMatrix TEqn
                (
                    fvm::ddt(T) == fvm::laplacian(DT, T) + fvOptions(T)
                );

                fvOptions.constrain(TEqn);

                TEqn.solve();

                fvOptions.correct(T);
            }

            {
                fvVectorMatrix DEqn
                (
                    fvm::d2dt2(D)
                 ==
                    fvm::laplacian(2*mu + lambda, D, "laplacian(DD,D)")
                  + divSigmaExp
                  + fvOptions.d2dt2(D)
                );

                if (thermalStress)
                {
                    const volScalarField& T = Tptr();
                    DEqn += fvc::grad(threeKalpha*T);
                }

                fvOptions.constrain(DEqn);

                initialResidual = DEqn.solve().max().initialResidual();

                if (!compactNormalStress)
                {
                    divSigmaExp = fvc::div(DEqn.flux());
                }
            }

            {
                volTensorField gradD(fvc::grad(D));
                sigmaD = mu*twoSymm(gradD) + (lambda*I)*tr(gradD);

                if (compactNormalStress)
                {
                    divSigmaExp = fvc::div
                    (
                        sigmaD - (2*mu + lambda)*gradD,
                        "div(sigmaD)"
                    );
                }
                else
                {
                    divSigmaExp += fvc::div(sigmaD);
                }
            }

        } while (initialResidual > convergenceTolerance && ++iCorr < nCorr);

        #include "calculateStress.H"

        Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
            << "  ClockTime = " << runTime.elapsedClockTime() << " s"
            << nl << endl;
    }

    Info<< "End\n" << endl;

    return 0;
}


// ************************************************************************* //
