Line data Source code
1 : //* This file is part of the MOOSE framework
2 : //* https://mooseframework.inl.gov
3 : //*
4 : //* All rights reserved, see COPYRIGHT for full restrictions
5 : //* https://github.com/idaholab/moose/blob/master/COPYRIGHT
6 : //*
7 : //* Licensed under LGPL 2.1, please see LICENSE for details
8 : //* https://www.gnu.org/licenses/lgpl-2.1.html
9 :
10 : #pragma once
11 :
12 : #include "TwoParameterPlasticityStressUpdate.h"
13 : #include "SolidMechanicsHardeningModel.h"
14 : #include "SolidMechanicsPlasticDruckerPrager.h"
15 :
16 : /**
17 : * CappedDruckerPragerStressUpdate performs the return-map
18 : * algorithm and associated stress updates for plastic
19 : * models that describe capped Drucker-Prager plasticity.
20 : *
21 : * This plastic model is ideally suited to a material (eg rock)
22 : * that has different compressive, tensile and shear
23 : * strengths. Any of these strengths may be set large to
24 : * accommodate special situations. For instance, setting
25 : * the compressive strength large is appropriate if there
26 : * is no chance of compressive failure in a model.
27 : *
28 : * This plastic model has two internal parameters:
29 : * - a "shear" internal parameter which parameterises the
30 : * amount of shear plastic strain. The cohesion, friction
31 : * angle, and dilation angle are assumed to be functions
32 : * of this internal parameter.
33 : * - a "tensile" internal parameter which parameterises the
34 : * amount of tensile plastic strain. The tensile strength
35 : * and compressive strength are assumed to be functions of
36 : * this internal parameter. This means, for instance, that
37 : * failure in tension can cause the compressive strenght
38 : * to soften, as would be expected in rock-mechanics
39 : * scenarios.
40 : *
41 : * This plasticity model assumes the elasticity tensor obeys:
42 : * E_ijkl s_kl = 2 E_0101 * s_ij, for any traceless tensor, s_ij.
43 : * (This expression defines the scalar quantity, Eqq,
44 : * which is just the shear modulus in the isotropic situation.)
45 : *
46 : * As of Feb2017, small tests suggest that this Material model
47 : * is marginally more efficient than ComputeMultiPlasticityStress
48 : * with a DruckerPragerHyperbolic user object, if the compressive
49 : * and tensile strengths are set large. Adding compressive or
50 : * tensile failure adds about 40% more computation time (on
51 : * average) which again appears to be better than
52 : * ComputeMultiPlasticityStress with DruckerPrager and MeanCap(s)
53 : * user objects.
54 : */
55 : class CappedDruckerPragerStressUpdate : public TwoParameterPlasticityStressUpdate
56 : {
57 : public:
58 : static InputParameters validParams();
59 :
60 : CappedDruckerPragerStressUpdate(const InputParameters & parameters);
61 :
62 : /**
63 : * Does the model require the elasticity tensor to be isotropic?
64 : */
65 324 : bool requiresIsotropicTensor() override { return true; }
66 :
67 414 : bool isIsotropic() override { return true; };
68 :
69 : protected:
70 : /// Hardening model for cohesion, friction and dilation angles
71 : const SolidMechanicsPlasticDruckerPrager & _dp;
72 :
73 : /// Hardening model for tensile strength
74 : const SolidMechanicsHardeningModel & _tstrength;
75 :
76 : /// Hardening model for compressive strength
77 : const SolidMechanicsHardeningModel & _cstrength;
78 :
79 : /// The cone vertex is smoothed by this amount
80 : const Real _small_smoother2;
81 :
82 : /// Initialize the NR proceedure from a guess coming from perfect plasticity
83 : const bool _perfect_guess;
84 :
85 : /**
86 : * This allows some simplification in the return-map process.
87 : * If the tensile yield function yf[1] >= 0 at the trial stress then
88 : * clearly the quadpoint is not going to fail in compression, so
89 : * _stress_return_type is set to no_compression, and every time
90 : * the compressive yield function is evaluated it is set -(very large).
91 : * If the compressive yield function yf[2] >= 0 at the trial stress
92 : * then clearly the quadpoint is not going to fail in tension, so
93 : * _stress_return_type is set to no_tension, and every time the
94 : * tensile yield function is evaluated it is set -(very large).
95 : * Otherwise (and at the very end after return-map) _stress_return_type
96 : * is set to nothing_special.
97 : */
98 : enum class StressReturnType
99 : {
100 : nothing_special,
101 : no_compression,
102 : no_tension
103 : } _stress_return_type;
104 :
105 : /**
106 : * If true, and if the trial stress exceeds the tensile strength,
107 : * then the user gaurantees that the returned stress will be
108 : * independent of the compressive strength.
109 : */
110 : const bool _small_dilation;
111 :
112 : /// trial value of q
113 : Real _in_q_trial;
114 :
115 : virtual void yieldFunctionValues(Real p,
116 : Real q,
117 : const std::vector<Real> & intnl,
118 : std::vector<Real> & yf) const override;
119 :
120 : virtual void computeAllQ(Real p,
121 : Real q,
122 : const std::vector<Real> & intnl,
123 : std::vector<yieldAndFlow> & all_q) const override;
124 :
125 : virtual void preReturnMap(Real p_trial,
126 : Real q_trial,
127 : const RankTwoTensor & stress_trial,
128 : const std::vector<Real> & intnl_old,
129 : const std::vector<Real> & yf,
130 : const RankFourTensor & Eijkl) override;
131 :
132 : virtual void initializeVars(Real p_trial,
133 : Real q_trial,
134 : const std::vector<Real> & intnl_old,
135 : Real & p,
136 : Real & q,
137 : Real & gaE,
138 : std::vector<Real> & intnl) const override;
139 :
140 : virtual void setIntnlValues(Real p_trial,
141 : Real q_trial,
142 : Real p,
143 : Real q,
144 : const std::vector<Real> & intnl_old,
145 : std::vector<Real> & intnl) const override;
146 :
147 : virtual void setIntnlDerivatives(Real p_trial,
148 : Real q_trial,
149 : Real p,
150 : Real q,
151 : const std::vector<Real> & intnl,
152 : std::vector<std::vector<Real>> & dintnl) const override;
153 :
154 : virtual void computePQ(const RankTwoTensor & stress, Real & p, Real & q) const override;
155 :
156 : virtual void initializeReturnProcess() override;
157 :
158 : virtual void finalizeReturnProcess(const RankTwoTensor & rotation_increment) override;
159 :
160 : virtual void setEppEqq(const RankFourTensor & Eijkl, Real & Epp, Real & Eqq) const override;
161 :
162 : virtual void setStressAfterReturn(const RankTwoTensor & stress_trial,
163 : Real p_ok,
164 : Real q_ok,
165 : Real gaE,
166 : const std::vector<Real> & intnl,
167 : const yieldAndFlow & smoothed_q,
168 : const RankFourTensor & Eijkl,
169 : RankTwoTensor & stress) const override;
170 :
171 : virtual void consistentTangentOperator(const RankTwoTensor & stress_trial,
172 : Real p_trial,
173 : Real q_trial,
174 : const RankTwoTensor & stress,
175 : Real p,
176 : Real q,
177 : Real gaE,
178 : const yieldAndFlow & smoothed_q,
179 : const RankFourTensor & Eijkl,
180 : bool compute_full_tangent_operator,
181 : RankFourTensor & cto) const override;
182 :
183 : virtual RankTwoTensor dpdstress(const RankTwoTensor & stress) const override;
184 :
185 : virtual RankFourTensor d2pdstress2(const RankTwoTensor & stress) const override;
186 :
187 : virtual RankTwoTensor dqdstress(const RankTwoTensor & stress) const override;
188 :
189 : virtual RankFourTensor d2qdstress2(const RankTwoTensor & stress) const override;
190 : };
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