AllenCahnElasticEnergyOffDiag.C

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//* This file is part of the MOOSE framework
//* https://www.mooseframework.org
//*
//* All rights reserved, see COPYRIGHT for full restrictions
//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
//*
//* Licensed under LGPL 2.1, please see LICENSE for details
//* https://www.gnu.org/licenses/lgpl-2.1.html
 
#include "AllenCahnElasticEnergyOffDiag.h"
#include "MathUtils.h"
#include "RankTwoTensor.h"
 
registerMooseObject("PhaseFieldApp", AllenCahnElasticEnergyOffDiag);
 
template <>
InputParameters
validParams<AllenCahnElasticEnergyOffDiag>()
{
  InputParameters params = validParams<Kernel>();
  params.addClassDescription("This kernel calculates off-diagonal Jacobian of elastic energy in "
                             "AllenCahn with respect to displacements");
  params.addCoupledVar("displacements",
                       "The vector of displacements suitable for the problem statement");
  params.addParam<MaterialPropertyName>(
      "F_name", "E_el", "Name of material property storing the elastic energy");
  params.addParam<MaterialPropertyName>("mob_name", "L", "The mobility used with the kernel");
  return params;
}
 
AllenCahnElasticEnergyOffDiag::AllenCahnElasticEnergyOffDiag(const InputParameters & parameters)
  : DerivativeMaterialInterface<JvarMapKernelInterface<Kernel>>(parameters),
    _L(getMaterialProperty<Real>("mob_name")),
    _ndisp(coupledComponents("displacements")),
    _disp_var(_ndisp),
    _d2Fdcdstrain(getMaterialProperty<RankTwoTensor>("d2Fdcdstrain"))
{
  for (unsigned int i = 0; i < _ndisp; ++i)
    _disp_var[i] = coupled("displacements", i);
}
 
Real
AllenCahnElasticEnergyOffDiag::computeQpOffDiagJacobian(unsigned int jvar)
{
  for (unsigned int c_comp = 0; c_comp < _ndisp; ++c_comp)
    if (jvar == _disp_var[c_comp])
    {
      const Real dxddFdc = _L[_qp] * _test[_i][_qp];
      const Real d2Fdcdstrain_comp =
          (_d2Fdcdstrain[_qp].column(c_comp) + _d2Fdcdstrain[_qp].row(c_comp)) / 2.0 *
          _grad_phi[_j][_qp];
      return dxddFdc * d2Fdcdstrain_comp;
    }
 
  return 0.0;
}