ElasticEnergyMaterial.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 "ElasticEnergyMaterial.h"
#include "RankTwoTensor.h"
#include "RankFourTensor.h"
 
registerMooseObject("PhaseFieldApp", ElasticEnergyMaterial);
 
template <>
InputParameters
validParams<ElasticEnergyMaterial>()
{
  InputParameters params = validParams<DerivativeFunctionMaterialBase>();
  params.addClassDescription("Free energy material for the elastic energy contributions.");
  params.addParam<std::string>("base_name", "Material property base name");
  params.addRequiredCoupledVar("args", "Arguments of F() - use vector coupling");
  params.addCoupledVar("displacement_gradients",
                       "Vector of displacement gradient variables (see "
                       "Modules/PhaseField/DisplacementGradients "
                       "action)");
  return params;
}
 
ElasticEnergyMaterial::ElasticEnergyMaterial(const InputParameters & parameters)
  : DerivativeFunctionMaterialBase(parameters),
    _base_name(isParamValid("base_name") ? getParam<std::string>("base_name") + "_" : ""),
    _stress(getMaterialPropertyByName<RankTwoTensor>(_base_name + "stress")),
    _elasticity_tensor(getMaterialPropertyByName<RankFourTensor>(_base_name + "elasticity_tensor")),
    _strain(getMaterialPropertyByName<RankTwoTensor>(_base_name + "elastic_strain"))
{
  _dstrain.resize(_nargs);
  _d2strain.resize(_nargs);
  _delasticity_tensor.resize(_nargs);
  _d2elasticity_tensor.resize(_nargs);
 
  // fetch stress and elasticity tensor derivatives (in simple eigenstrain models this is is only
  // w.r.t. 'c')
  for (unsigned int i = 0; i < _nargs; ++i)
  {
    _dstrain[i] = &getMaterialPropertyDerivativeByName<RankTwoTensor>(_base_name + "elastic_strain",
                                                                      _arg_names[i]);
    _delasticity_tensor[i] = &getMaterialPropertyDerivativeByName<RankFourTensor>(
        _base_name + "elasticity_tensor", _arg_names[i]);
 
    _d2strain[i].resize(_nargs);
    _d2elasticity_tensor[i].resize(_nargs);
 
    for (unsigned int j = 0; j < _nargs; ++j)
    {
      _d2strain[i][j] = &getMaterialPropertyDerivativeByName<RankTwoTensor>(
          _base_name + "elastic_strain", _arg_names[i], _arg_names[j]);
      _d2elasticity_tensor[i][j] = &getMaterialPropertyDerivativeByName<RankFourTensor>(
          _base_name + "elasticity_tensor", _arg_names[i], _arg_names[j]);
    }
  }
}
 
void
ElasticEnergyMaterial::initialSetup()
{
  validateCoupling<RankTwoTensor>(_base_name + "elastic_strain");
  validateCoupling<RankFourTensor>(_base_name + "elasticity_tensor");
}
 
Real
ElasticEnergyMaterial::computeF()
{
  return 0.5 * _stress[_qp].doubleContraction(_strain[_qp]);
}
 
Real
ElasticEnergyMaterial::computeDF(unsigned int i_var)
{
  unsigned int i = argIndex(i_var);
 
  // product rule d/di computeF (doubleContraction commutes)
  return 0.5 * ((*_delasticity_tensor[i])[_qp] * _strain[_qp]).doubleContraction(_strain[_qp]) +
         (_elasticity_tensor[_qp] * (*_dstrain[i])[_qp]).doubleContraction(_strain[_qp]);
}
 
Real
ElasticEnergyMaterial::computeD2F(unsigned int i_var, unsigned int j_var)
{
  unsigned int i = argIndex(i_var);
  unsigned int j = argIndex(j_var);
 
  // product rule d/dj computeDF
  // TODO: simplify because doubleContraction commutes
  return 0.5 * (((*_d2elasticity_tensor[i][j])[_qp] * _strain[_qp] +
                 (*_delasticity_tensor[i])[_qp] * (*_dstrain[j])[_qp] +
                 (*_delasticity_tensor[j])[_qp] * (*_dstrain[i])[_qp] +
                 _elasticity_tensor[_qp] * (*_d2strain[i][j])[_qp])
                    .doubleContraction(_strain[_qp]) +
                ((*_delasticity_tensor[i])[_qp] * _strain[_qp] +
                 _elasticity_tensor[_qp] * (*_dstrain[i])[_qp])
                    .doubleContraction((*_dstrain[j])[_qp])
 
                +
                ( // dstress/dj
                    (*_delasticity_tensor[j])[_qp] * _strain[_qp] +
                    _elasticity_tensor[_qp] * (*_dstrain[j])[_qp])
                    .doubleContraction((*_dstrain[i])[_qp]) +
                _stress[_qp].doubleContraction((*_d2strain[i][j])[_qp]));
}