ComputeExtraStressVDWGas.C

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//* This file is part of the MOOSE framework
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//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
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//* https://www.gnu.org/licenses/lgpl-2.1.html
 
#include "ComputeExtraStressVDWGas.h"
 
registerMooseObject("TensorMechanicsApp", ComputeExtraStressVDWGas);
 
defineLegacyParams(ComputeExtraStressVDWGas);
 
InputParameters
ComputeExtraStressVDWGas::validParams()
{
  InputParameters params = ComputeExtraStressBase::validParams();
  params.addClassDescription(
      "Computes a hydrostatic stress corresponding to the pressure of a van der Waals gas that is "
      "added as an extra_stress to the stress computed by the constitutive model");
  params.addRequiredParam<MaterialPropertyName>(
      "b", "Hard-sphere exclusion volume of van der Waals gas atoms in nm^3");
  params.addRequiredParam<MaterialPropertyName>("Va", "Atomic volume of lattice atoms in nm^3");
  params.addRequiredParam<MaterialPropertyName>("T", "Temperature in K");
  params.addRequiredCoupledVar("cg", "Gas concentration (relative to lattice atoms)");
  params.addParam<Real>("nondim_factor",
                        1.0,
                        "Optional factor to non-dimensionalize pressure (pressure is calculated in "
                        "Pa, set this factor to characteristic energy density used for "
                        "non-dimensionalization if desired)");
  return params;
}
 
ComputeExtraStressVDWGas::ComputeExtraStressVDWGas(const InputParameters & parameters)
  : ComputeExtraStressBase(parameters),
    _b(getMaterialProperty<Real>("b")),
    _Va(getMaterialProperty<Real>("Va")),
    _T(getMaterialProperty<Real>("T")),
    _cg(coupledValue("cg")),
    _nondim_factor(getParam<Real>("nondim_factor")),
    _kB(1.38064852e-23) // Boltzmann constant in J/K
{
}
 
void
ComputeExtraStressVDWGas::computeQpExtraStress()
{
  _extra_stress[_qp].zero();
  _extra_stress[_qp].addIa(-_kB * _T[_qp] / (_Va[_qp] / _cg[_qp] - _b[_qp]) * 1.0e27 /
                           _nondim_factor);
}