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;

    volTensorField Finv = inv(F);
    volSymmTensorField epsilonAlmansi
      (
       IOobject
       (
	"epsilonAlmansi",
	runTime.timeName(),
	mesh,
	IOobject::NO_READ,
	IOobject::AUTO_WRITE
	),
       symm(Finv & epsilon & Finv.T())
       );

    //- boundary traction
    volVectorField traction
      (
       IOobject
       (
	"tractionCauchy",
	runTime.timeName(),
	mesh,
	IOobject::NO_READ,
	IOobject::AUTO_WRITE
	),
       mesh,
       dimensionedVector("zero", dimForce/dimArea, vector::zero)
       );
    forAll(traction.boundaryField(), patchi)
      {
	tensorField Fpatch = I + gradU.boundaryField()[patchi];

	traction.boundaryField()[patchi] =
	  n.boundaryField()[patchi] & (sigma.boundaryField()[patchi] & Fpatch);
      }

    runTime.write();
  }