Compute2DFiniteStrain.C

Go to the documentation of this file.

//* This file is part of the MOOSE framework
//* https://mooseframework.inl.gov
//*
//* 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 "Compute2DFiniteStrain.h"
 
#include "libmesh/quadrature.h"
 
InputParameters
Compute2DFiniteStrain::validParams()
{
  InputParameters params = ComputeFiniteStrain::validParams();
  params.addClassDescription(
      "Compute a strain increment and rotation increment for finite strains in 2D geometries.");
 
  MooseEnum outOfPlaneDirection("x y z", "z");
  params.addParam<MooseEnum>(
      "out_of_plane_direction", outOfPlaneDirection, "The direction of the out-of-plane strain.");
  return params;
}
 
Compute2DFiniteStrain::Compute2DFiniteStrain(const InputParameters & parameters)
  : ComputeFiniteStrain(parameters),
    _out_of_plane_direction(getParam<MooseEnum>("out_of_plane_direction"))
{
}
 
void
Compute2DFiniteStrain::initialSetup()
{
  for (unsigned int i = 0; i < 3; ++i)
  {
    if (_out_of_plane_direction == i)
    {
      _disp[i] = &_zero;
      _grad_disp[i] = &_grad_zero;
    }
    else
    {
      _disp[i] = &coupledValue("displacements", i);
      _grad_disp[i] = &coupledGradient("displacements", i);
    }
 
    if (_fe_problem.isTransient() && i != _out_of_plane_direction)
      _grad_disp_old[i] = &coupledGradientOld("displacements", i);
    else
      _grad_disp_old[i] = &_grad_zero;
  }
}
 
void
Compute2DFiniteStrain::computeProperties()
{
  RankTwoTensor ave_Fhat;
  Real ave_dfgrd_det = 0.0;
 
  for (_qp = 0; _qp < _qrule->n_points(); ++_qp)
  {
    // Deformation gradient calculation for 2D problems
    auto A = RankTwoTensor::initializeFromRows(
        (*_grad_disp[0])[_qp], (*_grad_disp[1])[_qp], (*_grad_disp[2])[_qp]);
 
    // Old Deformation gradient
    auto Fbar = RankTwoTensor::initializeFromRows(
        (*_grad_disp_old[0])[_qp], (*_grad_disp_old[1])[_qp], (*_grad_disp_old[2])[_qp]);
 
    // Compute the displacement gradient for the out of plane direction for plane strain,
    // generalized plane strain, or axisymmetric problems
 
    A(_out_of_plane_direction, _out_of_plane_direction) = computeOutOfPlaneGradDisp();
    Fbar(_out_of_plane_direction, _out_of_plane_direction) = computeOutOfPlaneGradDispOld();
 
    // Gauss point deformation gradient
    _deformation_gradient[_qp] = A;
    _deformation_gradient[_qp].addIa(1.0);
 
    // deformation gradient midpoint
    if (_use_hw)
    {
      (*_def_grad_mid)[_qp].setToIdentity();
      (*_def_grad_mid)[_qp] += 0.5 * (A + Fbar);
    }
 
    A -= Fbar; // very nearly A = gradU - gradUold
 
    // _f_bar = dDU/dX_o
    if (_use_hw)
      (*_f_bar)[_qp] = A;
 
    Fbar.addIa(1.0); // Fbar = ( I + gradUold)
 
    // Incremental deformation gradient _Fhat = I + A Fbar^-1
    _Fhat[_qp] = A * Fbar.inverse();
    _Fhat[_qp].addIa(1.0);
 
    if (_volumetric_locking_correction)
    {
      // Calculate average _Fhat for volumetric locking correction
      ave_Fhat += _Fhat[_qp] * _JxW[_qp] * _coord[_qp];
 
      // Average deformation gradient
      ave_dfgrd_det += _deformation_gradient[_qp].det() * _JxW[_qp] * _coord[_qp];
    }
  }
  if (_volumetric_locking_correction)
  {
    // needed for volumetric locking correction
    ave_Fhat /= _current_elem_volume;
    // average deformation gradient
    ave_dfgrd_det /= _current_elem_volume;
  }
  for (_qp = 0; _qp < _qrule->n_points(); ++_qp)
  {
    if (_volumetric_locking_correction)
    {
      // Finalize volumetric locking correction
      _Fhat[_qp] *= std::cbrt(ave_Fhat.det() / _Fhat[_qp].det());
      // Volumetric locking correction
      _deformation_gradient[_qp] *= std::cbrt(ave_dfgrd_det / _deformation_gradient[_qp].det());
    }
 
    computeQpStrain();
  }
}
 
void
Compute2DFiniteStrain::displacementIntegrityCheck()
{
  if (_out_of_plane_direction != 2 && _ndisp != 3)
    mooseError("For 2D simulations where the out-of-plane direction is x or y the number of "
               "supplied displacements must be three.");
  else if (_out_of_plane_direction == 2 && _ndisp != 2)
    mooseError("For 2D simulations where the out-of-plane direction is z the number of supplied "
               "displacements must be two.");
}