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Compute2DFiniteStrain.C
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1 /****************************************************************/
2 /* MOOSE - Multiphysics Object Oriented Simulation Environment */
3 /* */
4 /* All contents are licensed under LGPL V2.1 */
5 /* See LICENSE for full restrictions */
6 /****************************************************************/
7 
9 
10 #include "libmesh/quadrature.h"
11 
12 template <>
13 InputParameters
15 {
16  InputParameters params = validParams<ComputeFiniteStrain>();
17  params.addClassDescription(
18  "Compute a strain increment and rotation increment for finite strains in 2D geometries.");
19  return params;
20 }
21 
22 Compute2DFiniteStrain::Compute2DFiniteStrain(const InputParameters & parameters)
23  : ComputeFiniteStrain(parameters)
24 {
25 }
26 
27 void
29 {
30  RankTwoTensor ave_Fhat;
31  Real ave_dfgrd_det = 0.0;
32 
33  for (_qp = 0; _qp < _qrule->n_points(); ++_qp)
34  {
35  // Deformation gradient calculation for 2D problems
36  // Note: x_disp is the radial displacement, y_disp is the axial displacement
37  RankTwoTensor A((*_grad_disp[0])[_qp],
38  (*_grad_disp[1])[_qp],
39  (*_grad_disp[2])[_qp]); // Deformation gradient
40  RankTwoTensor Fbar((*_grad_disp_old[0])[_qp],
41  (*_grad_disp_old[1])[_qp],
42  (*_grad_disp_old[2])[_qp]); // Old Deformation gradient
43 
44  // Compute the displacement gradient (2,2) value for plane strain, generalized plane strain, or
45  // axisymmetric problems
46  A(2, 2) = computeGradDispZZ();
47  Fbar(2, 2) = computeGradDispZZOld();
48 
49  // Gauss point deformation gradient
50  _deformation_gradient[_qp] = A;
51  _deformation_gradient[_qp].addIa(1.0);
52 
53  A -= Fbar; // very nearly A = gradU - gradUold, adapted to cylindrical coords
54 
55  Fbar.addIa(1.0); // Fbar = ( I + gradUold)
56 
57  // Incremental deformation gradient _Fhat = I + A Fbar^-1
58  _Fhat[_qp] = A * Fbar.inverse();
59  _Fhat[_qp].addIa(1.0);
60 
62  {
63  // Calculate average _Fhat for volumetric locking correction
64  ave_Fhat += _Fhat[_qp] * _JxW[_qp] * _coord[_qp];
65 
66  // Average deformation gradient
67  ave_dfgrd_det += _deformation_gradient[_qp].det() * _JxW[_qp] * _coord[_qp];
68  }
69  }
71  {
72  // needed for volumetric locking correction
73  ave_Fhat /= _current_elem_volume;
74  // average deformation gradient
75  ave_dfgrd_det /= _current_elem_volume;
76  }
77  for (_qp = 0; _qp < _qrule->n_points(); ++_qp)
78  {
80  {
81  // Finalize volumetric locking correction
82  _Fhat[_qp] *= std::cbrt(ave_Fhat.det() / _Fhat[_qp].det());
83  // Volumetric locking correction
84  _deformation_gradient[_qp] *= std::cbrt(ave_dfgrd_det / _deformation_gradient[_qp].det());
85  }
86 
88  }
89 }
virtual void computeProperties()
virtual Real computeGradDispZZ()=0
Computes the current out-of-plane displacement gradient; as a virtual function, this function is over...
const Real & _current_elem_volume
Compute2DFiniteStrain(const InputParameters &parameters)
MaterialProperty< RankTwoTensor > & _deformation_gradient
InputParameters validParams< ComputeFiniteStrain >()
InputParameters validParams< Compute2DFiniteStrain >()
virtual void computeQpStrain()
ComputeFiniteStrain defines a strain increment and rotation increment, for finite strains...
std::vector< const VariableGradient * > _grad_disp_old
std::vector< RankTwoTensor > _Fhat
virtual Real computeGradDispZZOld()=0
Computes the old out-of-plane displacement gradient; as a virtual function, this function is overwrit...
std::vector< const VariableGradient * > _grad_disp