foam-extend4.1-coherent-io/applications/solvers/solidMechanics/elasticNonLinTLSolidFoam/writeFields.H

if (runTime.outputTime())
{
    volScalarField epsilonEq
    (
        IOobject
        (
            "epsilonEq",
            runTime.timeName(),
            mesh,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
        ),
        sqrt((2.0/3.0)*magSqr(dev(epsilon)))
    );

    Info<< "Max epsilonEq = " << max(epsilonEq).value()
        << endl;

    volScalarField sigmaEq
    (
        IOobject
        (
            "sigmaEq",
            runTime.timeName(),
            mesh,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
        ),
        sqrt((3.0/2.0)*magSqr(dev(sigma)))
    );

    Info<< "Max sigmaEq = " << max(sigmaEq).value()
        << endl;

    //- Calculate Cauchy stress
    volTensorField F = I + gradU;
    volScalarField J = det(F);

    //- update density
    rho = rho/J;

    volSymmTensorField sigmaCauchy
    (
        IOobject
        (
             "sigmaCauchy",
             runTime.timeName(),
             mesh,
             IOobject::NO_READ,
             IOobject::AUTO_WRITE
        ),
        (1/J) * symm(F.T() & sigma & F)
    );

    //- Cauchy von Mises stress
    volScalarField sigmaCauchyEq
    (
        IOobject
        (
            "sigmaCauchyEq",
            runTime.timeName(),
            mesh,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
       ),
       sqrt((3.0/2.0)*magSqr(dev(sigmaCauchy)))
   );

    Info<< "Max sigmaCauchyEq = " << max(sigmaCauchyEq).value()
        << endl;

    //- write boundary forces
    //- integrate (sigma2PK & F) over reference area
    //- which is equivalent to integrating sigmaCauchy
    //- over the deformed area
    Info << nl;
    forAll(mesh.boundary(), patchi)
    {
        Info << "Patch " << mesh.boundary()[patchi].name() << endl;
        tensorField F = I + gradU.boundaryField()[patchi];
        vectorField totalForce = mesh.Sf().boundaryField()[patchi] & (sigma.boundaryField()[patchi] & F);

        vector force = sum( totalForce );
        Info << "\ttotal force is " << force << " N" << endl;

        tensorField Finv = inv(F);
        vectorField nCurrent = Finv & n.boundaryField()[patchi];
        nCurrent /= mag(nCurrent);
        scalar normalForce = sum( nCurrent & totalForce );
        Info << "\tnormal force is " << normalForce << " N" << endl;
        scalar shearForce = mag(sum( (I - sqr(nCurrent)) & totalForce ));
        Info << "\tshear force is " << shearForce << " N" << endl << endl;;
    }


    //- move mesh for visualisation and move it back after writing
    vectorField oldPoints = mesh.allPoints();
#   include "moveMeshLeastSquares.H"

    runTime.write();

    //- move mesh back
    mesh.movePoints(oldPoints);
}