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TensileStressUpdate Class Reference

TensileStressUpdate implements rate-independent associative tensile failure ("Rankine" plasticity) with hardening/softening. More...

#include <TensileStressUpdate.h>

Inheritance diagram for TensileStressUpdate:
[legend]

Public Member Functions

 TensileStressUpdate (const InputParameters &parameters)
 
bool requiresIsotropicTensor () override
 Does the model require the elasticity tensor to be isotropic? More...
 
void setQp (unsigned int qp)
 Sets the value of the global variable _qp for inheriting classes. More...
 
virtual Real computeTimeStepLimit ()
 
void resetQpProperties () final
 Retained as empty methods to avoid a warning from Material.C in framework. These methods are unused in all inheriting classes and should not be overwritten. More...
 
void resetProperties () final
 

Protected Member Functions

virtual Real tensile_strength (const Real internal_param) const
 tensile strength as a function of residual value, rate, and internal_param More...
 
virtual Real dtensile_strength (const Real internal_param) const
 d(tensile strength)/d(internal_param) as a function of residual value, rate, and internal_param More...
 
void computeStressParams (const RankTwoTensor &stress, std::vector< Real > &stress_params) const override
 Computes stress_params, given stress. More...
 
std::vector< RankTwoTensor > dstress_param_dstress (const RankTwoTensor &stress) const override
 d(stress_param[i])/d(stress) at given stress More...
 
std::vector< RankFourTensor > d2stress_param_dstress (const RankTwoTensor &stress) const override
 d2(stress_param[i])/d(stress)/d(stress) at given stress More...
 
virtual void setStressAfterReturnV (const RankTwoTensor &stress_trial, const std::vector< Real > &stress_params, Real gaE, const std::vector< Real > &intnl, const yieldAndFlow &smoothed_q, const RankFourTensor &Eijkl, RankTwoTensor &stress) const override
 Sets stress from the admissible parameters. More...
 
virtual void preReturnMapV (const std::vector< Real > &trial_stress_params, const RankTwoTensor &stress_trial, const std::vector< Real > &intnl_old, const std::vector< Real > &yf, const RankFourTensor &Eijkl) override
 Derived classes may employ this function to record stuff or do other computations prior to the return-mapping algorithm. More...
 
void setEffectiveElasticity (const RankFourTensor &Eijkl) override
 Sets _Eij and _En and _Cij. More...
 
void yieldFunctionValuesV (const std::vector< Real > &stress_params, const std::vector< Real > &intnl, std::vector< Real > &yf) const override
 Computes the values of the yield functions, given stress_params and intnl parameters. More...
 
void computeAllQV (const std::vector< Real > &stress_params, const std::vector< Real > &intnl, std::vector< yieldAndFlow > &all_q) const override
 Completely fills all_q with correct values. More...
 
void initializeVarsV (const std::vector< Real > &trial_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &stress_params, Real &gaE, std::vector< Real > &intnl) const override
 Sets (stress_params, intnl) at "good guesses" of the solution to the Return-Map algorithm. More...
 
void setIntnlValuesV (const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &intnl) const override
 Sets the internal parameters based on the trial values of stress_params, their current values, and the old values of the internal parameters. More...
 
void setIntnlDerivativesV (const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl, std::vector< std::vector< Real >> &dintnl) const override
 Sets the derivatives of internal parameters, based on the trial values of stress_params, their current values, and the current values of the internal parameters. More...
 
virtual void consistentTangentOperatorV (const RankTwoTensor &stress_trial, const std::vector< Real > &trial_stress_params, const RankTwoTensor &stress, const std::vector< Real > &stress_params, Real gaE, const yieldAndFlow &smoothed_q, const RankFourTensor &Eijkl, bool compute_full_tangent_operator, const std::vector< std::vector< Real >> &dvar_dtrial, RankFourTensor &cto) override
 Calculates the consistent tangent operator. More...
 
virtual void initQpStatefulProperties () override
 
virtual void updateState (RankTwoTensor &strain_increment, RankTwoTensor &inelastic_strain_increment, const RankTwoTensor &rotation_increment, RankTwoTensor &stress_new, const RankTwoTensor &stress_old, const RankFourTensor &elasticity_tensor, const RankTwoTensor &elastic_strain_old, bool compute_full_tangent_operator, RankFourTensor &tangent_operator) override
 Given a strain increment that results in a trial stress, perform some procedure (such as an iterative return-mapping process) to produce an admissible stress, an elastic strain increment and an inelastic strain increment. More...
 
virtual void propagateQpStatefulProperties () override
 If updateState is not called during a timestep, this will be. More...
 
Real yieldF (const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
 Computes the smoothed yield function. More...
 
Real yieldF (const std::vector< Real > &yfs) const
 Computes the smoothed yield function. More...
 
Real ismoother (Real f_diff) const
 Smooths yield functions. More...
 
Real smoother (Real f_diff) const
 Derivative of ismoother. More...
 
Real dsmoother (Real f_diff) const
 Derivative of smoother. More...
 
yieldAndFlow smoothAllQuantities (const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
 Calculates all yield functions and derivatives, and then performs the smoothing scheme. More...
 
int lineSearch (Real &res2, std::vector< Real > &stress_params, Real &gaE, const std::vector< Real > &trial_stress_params, yieldAndFlow &smoothed_q, const std::vector< Real > &intnl_ok, std::vector< Real > &intnl, std::vector< Real > &rhs, Real &linesearch_needed) const
 Performs a line-search to find stress_params and gaE Upon entry: More...
 
int nrStep (const yieldAndFlow &smoothed_q, const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, const std::vector< Real > &intnl, Real gaE, std::vector< Real > &rhs) const
 Performs a Newton-Raphson step to attempt to zero rhs Upon return, rhs will contain the solution. More...
 
Real calculateRes2 (const std::vector< Real > &rhs) const
 Calculates the residual-squared for the Newton-Raphson + line-search. More...
 
void calculateRHS (const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, Real gaE, const yieldAndFlow &smoothed_q, std::vector< Real > &rhs) const
 Calculates the RHS in the following 0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, j] * dg/dS[j] 0 = rhs[1] = S[1] - S[1]^trial + ga * E[1, j] * dg/dS[j] ... More...
 
void dnRHSdVar (const yieldAndFlow &smoothed_q, const std::vector< std::vector< Real >> &dintnl, const std::vector< Real > &stress_params, Real gaE, std::vector< double > &jac) const
 Derivative of -RHS with respect to the stress_params and gaE, placed into an array ready for solving the linear system using LAPACK gsev. More...
 
virtual void errorHandler (const std::string &message) const
 Performs any necessary cleaning-up, then throw MooseException(message) More...
 
virtual void initializeReturnProcess ()
 Derived classes may use this to perform calculations before any return-map process is performed, for instance, to initialize variables. More...
 
virtual void finalizeReturnProcess (const RankTwoTensor &rotation_increment)
 Derived classes may use this to perform calculations after the return-map process has completed successfully in stress_param space but before the returned stress tensor has been calculcated. More...
 
virtual void setInelasticStrainIncrementAfterReturn (const RankTwoTensor &stress_trial, Real gaE, const yieldAndFlow &smoothed_q, const RankFourTensor &elasticity_tensor, const RankTwoTensor &returned_stress, RankTwoTensor &inelastic_strain_increment) const
 Sets inelastic strain increment from the returned configuration This is called after the return-map process has completed successfully in stress_param space, just after finalizeReturnProcess has been called. More...
 
void dVardTrial (bool elastic_only, const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, Real gaE, const std::vector< Real > &intnl, const yieldAndFlow &smoothed_q, Real step_size, bool compute_full_tangent_operator, std::vector< std::vector< Real >> &dvar_dtrial) const
 Calculates derivatives of the stress_params and gaE with repect to the trial values of the stress_params for the (sub)strain increment. More...
 
bool precisionLoss (const std::vector< Real > &solution, const std::vector< Real > &stress_params, Real gaE) const
 Check whether precision loss has occurred. More...
 

Protected Attributes

const TensorMechanicsHardeningModel_strength
 Hardening model for tensile strength. More...
 
const bool _perfect_guess
 Whether to provide an estimate of the returned stress, based on perfect plasticity. More...
 
RankTwoTensor _eigvecs
 Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to stress space. More...
 
const unsigned _num_sp
 Number of stress parameters. More...
 
const std::vector< Real > _definitely_ok_sp
 An admissible value of stress_params at the initial time. More...
 
std::vector< std::vector< Real > > _Eij
 E[i, j] in the system of equations to be solved. More...
 
Real _En
 normalising factor More...
 
std::vector< std::vector< Real > > _Cij
 _Cij[i, j] * _Eij[j, k] = 1 iff j == k More...
 
const unsigned _num_yf
 Number of yield functions. More...
 
const unsigned _num_intnl
 Number of internal parameters. More...
 
const std::string _base_name
 String prepended to various MaterialProperties that are defined by this class. More...
 
const unsigned _max_nr_its
 Maximum number of Newton-Raphson iterations allowed in the return-map process. More...
 
const bool _perform_finite_strain_rotations
 Whether to perform finite-strain rotations. More...
 
const Real _smoothing_tol
 Smoothing tolerance: edges of the yield surface get smoothed by this amount. More...
 
const Real _f_tol
 The yield-function tolerance. More...
 
const Real _f_tol2
 Square of the yield-function tolerance. More...
 
const Real _min_step_size
 In order to help the Newton-Raphson procedure, the applied strain increment may be applied in sub-increments of size greater than this value. More...
 
bool _step_one
 handles case of initial_stress that is inadmissible being supplied More...
 
const bool _warn_about_precision_loss
 Output a warning message if precision loss is encountered during the return-map process. More...
 
MaterialProperty< RankTwoTensor > & _plastic_strain
 plastic strain More...
 
const MaterialProperty< RankTwoTensor > & _plastic_strain_old
 Old value of plastic strain. More...
 
MaterialProperty< std::vector< Real > > & _intnl
 internal parameters More...
 
const MaterialProperty< std::vector< Real > > & _intnl_old
 old values of internal parameters More...
 
MaterialProperty< std::vector< Real > > & _yf
 yield functions More...
 
MaterialProperty< Real > & _iter
 Number of Newton-Raphson iterations used in the return-map. More...
 
MaterialProperty< Real > & _linesearch_needed
 Whether a line-search was needed in the latest Newton-Raphson process (1 if true, 0 otherwise) More...
 

Static Protected Attributes

static constexpr unsigned _tensor_dimensionality = 3
 Internal dimensionality of tensors (currently this is 3 throughout tensor_mechanics) More...
 

Detailed Description

TensileStressUpdate implements rate-independent associative tensile failure ("Rankine" plasticity) with hardening/softening.

Definition at line 22 of file TensileStressUpdate.h.

Constructor & Destructor Documentation

TensileStressUpdate::TensileStressUpdate ( const InputParameters &  parameters)

Definition at line 29 of file TensileStressUpdate.C.

30  : MultiParameterPlasticityStressUpdate(parameters, 3, 3, 1),
31  _strength(getUserObject<TensorMechanicsHardeningModel>("tensile_strength")),
32  _perfect_guess(getParam<bool>("perfect_guess")),
33  _eigvecs(RankTwoTensor())
34 {
35 }
MultiParameterPlasticityStressUpdate(const InputParameters &parameters, unsigned num_sp, unsigned num_yf, unsigned num_intnl)
RankTwoTensor _eigvecs
Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to s...
const TensorMechanicsHardeningModel & _strength
Hardening model for tensile strength.
const bool _perfect_guess
Whether to provide an estimate of the returned stress, based on perfect plasticity.

Member Function Documentation

Real MultiParameterPlasticityStressUpdate::calculateRes2 ( const std::vector< Real > &  rhs) const
protectedinherited

Calculates the residual-squared for the Newton-Raphson + line-search.

Parameters
rhs[in]The RHS vector
Returns
sum_i (rhs[i] * rhs[i])

Definition at line 730 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::lineSearch(), MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

731 {
732  Real res2 = 0.0;
733  for (const auto & r : rhs)
734  res2 += r * r;
735  return res2;
736 }
void MultiParameterPlasticityStressUpdate::calculateRHS ( const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  stress_params,
Real  gaE,
const yieldAndFlow smoothed_q,
std::vector< Real > &  rhs 
) const
protectedinherited

Calculates the RHS in the following 0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, j] * dg/dS[j] 0 = rhs[1] = S[1] - S[1]^trial + ga * E[1, j] * dg/dS[j] ...

0 = rhs[N-1] = S[N-1] - S[N-1]^trial + ga * E[N-1, j] * dg/dS[j] 0 = rhs[N] = f(S, intnl) where N = _num_sp

Parameters
trial_stress_params[in]The trial stress parameters for this (sub)strain increment, S[:]^trial
stress_params[in]The current stress parameters, S[:]
gaE[in]ga*_En (the normalisation with _En is so that gaE is of similar magnitude to S)
smoothed_q[in]Holds the current value of yield function and derivatives evaluated at the current stress parameters and the current internal parameters
rhs[out]The result

Definition at line 739 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::lineSearch(), MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

744 {
745  const Real ga = gaE / _En;
746  for (unsigned i = 0; i < _num_sp; ++i)
747  {
748  rhs[i] = stress_params[i] - trial_stress_params[i];
749  for (unsigned j = 0; j < _num_sp; ++j)
750  rhs[i] += ga * _Eij[i][j] * smoothed_q.dg[j];
751  }
752  rhs[_num_sp] = smoothed_q.f;
753 }
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
const unsigned _num_sp
Number of stress parameters.
void TensileStressUpdate::computeAllQV ( const std::vector< Real > &  stress_params,
const std::vector< Real > &  intnl,
std::vector< yieldAndFlow > &  all_q 
) const
overrideprotectedvirtual

Completely fills all_q with correct values.

These values are: (1) the yield function values, yf[i] (2) d(yf[i])/d(stress_params[j]) (3) d(yf[i])/d(intnl[j]) (4) d(flowPotential[i])/d(stress_params[j]) (5) d2(flowPotential[i])/d(stress_params[j])/d(stress_params[k]) (6) d2(flowPotential[i])/d(stress_params[j])/d(intnl[k])

Parameters
stress_params[in]The stress parameters
intnl[in]The internal parameters
[out]all_qAll the desired quantities

Implements MultiParameterPlasticityStressUpdate.

Definition at line 104 of file TensileStressUpdate.C.

107 {
108  const Real ts = tensile_strength(intnl[0]);
109  const Real dts = dtensile_strength(intnl[0]);
110 
111  // yield functions. See comment in yieldFunctionValuesV
112  all_q[0].f = stress_params[2] - ts;
113  all_q[1].f = stress_params[1] - ts;
114  all_q[2].f = stress_params[0] - ts;
115 
116  // d(yield function)/d(stress_params)
117  for (unsigned yf = 0; yf < _num_yf; ++yf)
118  for (unsigned a = 0; a < _num_sp; ++a)
119  all_q[yf].df[a] = 0.0;
120  all_q[0].df[2] = 1.0;
121  all_q[1].df[1] = 1.0;
122  all_q[2].df[0] = 1.0;
123 
124  // d(yield function)/d(intnl)
125  for (unsigned yf = 0; yf < _num_yf; ++yf)
126  all_q[yf].df_di[0] = -dts;
127 
128  // the flow potential is just the yield function
129  // d(flow potential)/d(stress_params)
130  for (unsigned yf = 0; yf < _num_yf; ++yf)
131  for (unsigned a = 0; a < _num_sp; ++a)
132  all_q[yf].dg[a] = all_q[yf].df[a];
133 
134  // d(flow potential)/d(stress_params)/d(intnl)
135  for (unsigned yf = 0; yf < _num_yf; ++yf)
136  for (unsigned a = 0; a < _num_sp; ++a)
137  all_q[yf].d2g_di[a][0] = 0.0;
138 
139  // d(flow potential)/d(stress_params)/d(stress_params)
140  for (unsigned yf = 0; yf < _num_yf; ++yf)
141  for (unsigned a = 0; a < _num_sp; ++a)
142  for (unsigned b = 0; b < _num_sp; ++b)
143  all_q[yf].d2g[a][b] = 0.0;
144 }
const unsigned _num_yf
Number of yield functions.
virtual Real dtensile_strength(const Real internal_param) const
d(tensile strength)/d(internal_param) as a function of residual value, rate, and internal_param ...
virtual Real tensile_strength(const Real internal_param) const
tensile strength as a function of residual value, rate, and internal_param
const unsigned _num_sp
Number of stress parameters.
void TensileStressUpdate::computeStressParams ( const RankTwoTensor &  stress,
std::vector< Real > &  stress_params 
) const
overrideprotectedvirtual

Computes stress_params, given stress.

Derived classes must override this

Parameters
stress[in]Stress tensor
stress_params[out]The compute stress_params

Implements MultiParameterPlasticityStressUpdate.

Definition at line 38 of file TensileStressUpdate.C.

40 {
41  // stress_params[0] = smallest eigenvalue, stress_params[2] = largest eigenvalue
42  stress.symmetricEigenvalues(stress_params);
43 }
Real StressUpdateBase::computeTimeStepLimit ( )
virtualinherited

Reimplemented in RadialReturnStressUpdate.

Definition at line 43 of file StressUpdateBase.C.

44 {
45  return std::numeric_limits<Real>::max();
46 }
void TensileStressUpdate::consistentTangentOperatorV ( const RankTwoTensor &  stress_trial,
const std::vector< Real > &  trial_stress_params,
const RankTwoTensor &  stress,
const std::vector< Real > &  stress_params,
Real  gaE,
const yieldAndFlow smoothed_q,
const RankFourTensor &  Eijkl,
bool  compute_full_tangent_operator,
const std::vector< std::vector< Real >> &  dvar_dtrial,
RankFourTensor &  cto 
)
overrideprotectedvirtual

Calculates the consistent tangent operator.

Derived classes may choose to override this for computational efficiency. The implementation in this class is quite expensive, even though it looks compact and clean, because of all the manipulations of RankFourTensors involved.

Parameters
stress_trial[in]the trial value of the stress tensor for this strain increment
trial_stress_params[in]the trial values of the stress_params for this strain increment
stress[in]the returned value of the stress tensor for this strain increment
stress_params[in]the returned value of the stress_params for this strain increment
gaE[in]the total value of that came from this strain increment
smoothed_q[in]contains the yield function and derivatives evaluated at (p, q)
Eijkl[in]The elasticity tensor
compute_full_tangent_operator[in]true if the full consistent tangent operator is needed, otherwise false
dvar_dtrial[in]dvar_dtrial[i][j] = d({stress_param[i],gaE})/d(trial_stress_param[j]) for this strain increment
[out]ctoThe consistent tangent operator

Reimplemented from MultiParameterPlasticityStressUpdate.

Definition at line 221 of file TensileStressUpdate.C.

231 {
232  cto = elasticity_tensor;
233  if (!compute_full_tangent_operator)
234  return;
235 
236  // dvar_dtrial has been computed already, so
237  // d(stress)/d(trial_stress) = d(eigvecs * stress_params * eigvecs.transpose())/d(trial_stress)
238  // eigvecs is a rotation matrix, rot(i, j) = e_j(i) = i^th component of j^th eigenvector
239  // d(rot_ij)/d(stress_kl) = d(e_j(i))/d(stress_kl)
240  // = sum_a 0.5 * e_a(i) * (e_a(k)e_j(l) + e_a(l)e_j(k)) / (la_j - la_a)
241  // = sum_a 0.5 * rot(i,a) * (rot(k,a)rot(l,j) + rot(l,a)*rot(k,j)) / (la_j - la_a)
242  RankFourTensor drot_dstress;
243  for (unsigned i = 0; i < _tensor_dimensionality; ++i)
244  for (unsigned j = 0; j < _tensor_dimensionality; ++j)
245  for (unsigned k = 0; k < _tensor_dimensionality; ++k)
246  for (unsigned l = 0; l < _tensor_dimensionality; ++l)
247  for (unsigned a = 0; a < _num_sp; ++a)
248  {
249  if (trial_stress_params[a] == trial_stress_params[j])
250  continue;
251  drot_dstress(i, j, k, l) += 0.5 * _eigvecs(i, a) * (_eigvecs(k, a) * _eigvecs(l, j) +
252  _eigvecs(l, a) * _eigvecs(k, j)) /
253  (trial_stress_params[j] - trial_stress_params[a]);
254  }
255 
256  const RankTwoTensor eT = _eigvecs.transpose();
257 
258  RankFourTensor dstress_dtrial;
259  for (unsigned i = 0; i < _tensor_dimensionality; ++i)
260  for (unsigned j = 0; j < _tensor_dimensionality; ++j)
261  for (unsigned k = 0; k < _tensor_dimensionality; ++k)
262  for (unsigned l = 0; l < _tensor_dimensionality; ++l)
263  for (unsigned a = 0; a < _num_sp; ++a)
264  dstress_dtrial(i, j, k, l) +=
265  drot_dstress(i, a, k, l) * stress_params[a] * eT(a, j) +
266  _eigvecs(i, a) * stress_params[a] * drot_dstress(j, a, k, l);
267 
268  const std::vector<RankTwoTensor> dsp_trial = dstress_param_dstress(stress_trial);
269  for (unsigned i = 0; i < _tensor_dimensionality; ++i)
270  for (unsigned j = 0; j < _tensor_dimensionality; ++j)
271  for (unsigned k = 0; k < _tensor_dimensionality; ++k)
272  for (unsigned l = 0; l < _tensor_dimensionality; ++l)
273  for (unsigned a = 0; a < _num_sp; ++a)
274  for (unsigned b = 0; b < _num_sp; ++b)
275  dstress_dtrial(i, j, k, l) +=
276  _eigvecs(i, a) * dvar_dtrial[a][b] * dsp_trial[b](k, l) * eT(a, j);
277 
278  cto = dstress_dtrial * elasticity_tensor;
279 }
RankTwoTensor _eigvecs
Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to s...
std::vector< RankTwoTensor > dstress_param_dstress(const RankTwoTensor &stress) const override
d(stress_param[i])/d(stress) at given stress
static constexpr unsigned _tensor_dimensionality
Internal dimensionality of tensors (currently this is 3 throughout tensor_mechanics) ...
const unsigned _num_sp
Number of stress parameters.
std::vector< RankFourTensor > TensileStressUpdate::d2stress_param_dstress ( const RankTwoTensor &  stress) const
overrideprotectedvirtual

d2(stress_param[i])/d(stress)/d(stress) at given stress

Parameters
stressstress tensor
Returns
d2(stress_param[:])/d(stress)/d(stress)

Implements MultiParameterPlasticityStressUpdate.

Definition at line 55 of file TensileStressUpdate.C.

56 {
57  std::vector<RankFourTensor> d2;
58  stress.d2symmetricEigenvalues(d2);
59  return d2;
60 }
void MultiParameterPlasticityStressUpdate::dnRHSdVar ( const yieldAndFlow smoothed_q,
const std::vector< std::vector< Real >> &  dintnl,
const std::vector< Real > &  stress_params,
Real  gaE,
std::vector< double > &  jac 
) const
protectedinherited

Derivative of -RHS with respect to the stress_params and gaE, placed into an array ready for solving the linear system using LAPACK gsev.

Parameters
smoothed_q[in]Holds the current value of yield function and derivatives evaluated at the current values of the stress_params and the internal parameters
dintnl[in]The derivatives of the internal parameters wrt the stress_params
stress_params[in]The current value of the stress_params during the Newton-Raphson process
gaE[in]The current value of gaE
jac[out]The outputted derivatives

Definition at line 756 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::dVardTrial(), MultiParameterPlasticityStressUpdate::nrStep(), and MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<().

761 {
762  for (auto & jac_entry : jac)
763  jac_entry = 0.0;
764 
765  const Real ga = gaE / _En;
766 
767  unsigned ind = 0;
768  for (unsigned var = 0; var < _num_sp; ++var)
769  {
770  for (unsigned rhs = 0; rhs < _num_sp; ++rhs)
771  {
772  if (var == rhs)
773  jac[ind] -= 1.0;
774  for (unsigned j = 0; j < _num_sp; ++j)
775  {
776  jac[ind] -= ga * _Eij[rhs][j] * smoothed_q.d2g[j][var];
777  for (unsigned k = 0; k < _num_intnl; ++k)
778  jac[ind] -= ga * _Eij[rhs][j] * smoothed_q.d2g_di[j][k] * dintnl[k][var];
779  }
780  ind++;
781  }
782  // now rhs = _num_sp (that is, the yield function)
783  jac[ind] -= smoothed_q.df[var];
784  for (unsigned k = 0; k < _num_intnl; ++k)
785  jac[ind] -= smoothed_q.df_di[k] * dintnl[k][var];
786  ind++;
787  }
788 
789  // now var = _num_sp (that is, gaE)
790  for (unsigned rhs = 0; rhs < _num_sp; ++rhs)
791  {
792  for (unsigned j = 0; j < _num_sp; ++j)
793  jac[ind] -= (1.0 / _En) * _Eij[rhs][j] * smoothed_q.dg[j];
794  ind++;
795  }
796  // now rhs = _num_sp (that is, the yield function)
797  jac[ind] = 0.0;
798 }
const unsigned _num_intnl
Number of internal parameters.
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
const unsigned _num_sp
Number of stress parameters.
Real MultiParameterPlasticityStressUpdate::dsmoother ( Real  f_diff) const
protectedinherited

Derivative of smoother.

Definition at line 473 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::smoothAllQuantities().

474 {
475  if (std::abs(f_diff) >= _smoothing_tol)
476  return 0.0;
477  return 0.25 * M_PI / _smoothing_tol * std::cos(f_diff * M_PI * 0.5 / _smoothing_tol);
478 }
const Real _smoothing_tol
Smoothing tolerance: edges of the yield surface get smoothed by this amount.
std::vector< RankTwoTensor > TensileStressUpdate::dstress_param_dstress ( const RankTwoTensor &  stress) const
overrideprotectedvirtual

d(stress_param[i])/d(stress) at given stress

Parameters
stressstress tensor
Returns
d(stress_param[:])/d(stress)

Implements MultiParameterPlasticityStressUpdate.

Definition at line 46 of file TensileStressUpdate.C.

Referenced by consistentTangentOperatorV().

47 {
48  std::vector<Real> sp;
49  std::vector<RankTwoTensor> dsp;
50  stress.dsymmetricEigenvalues(sp, dsp);
51  return dsp;
52 }
Real TensileStressUpdate::dtensile_strength ( const Real  internal_param) const
protectedvirtual

d(tensile strength)/d(internal_param) as a function of residual value, rate, and internal_param

Definition at line 215 of file TensileStressUpdate.C.

Referenced by computeAllQV().

216 {
217  return _strength.derivative(internal_param);
218 }
virtual Real derivative(Real intnl) const
const TensorMechanicsHardeningModel & _strength
Hardening model for tensile strength.
void MultiParameterPlasticityStressUpdate::dVardTrial ( bool  elastic_only,
const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  stress_params,
Real  gaE,
const std::vector< Real > &  intnl,
const yieldAndFlow smoothed_q,
Real  step_size,
bool  compute_full_tangent_operator,
std::vector< std::vector< Real >> &  dvar_dtrial 
) const
protectedinherited

Calculates derivatives of the stress_params and gaE with repect to the trial values of the stress_params for the (sub)strain increment.

After the strain increment has been fully applied, dvar_dtrial will contain the result appropriate to the full strain increment. Before that time (if applying in sub-strain increments) it will contain the result appropriate to the amount of strain increment applied successfully.

Parameters
elastic_only[in]whether this was an elastic step: if so then the updates to dvar_dtrial are fairly trivial
trial_stress_params[in]Trial values of stress_params for this (sub)strain increment
stress_params[in]Returned values of stress_params for this (sub)strain increment
gaE[in]the value of gaE that came from this (sub)strain increment
intnl[in]the value of the internal parameters at the returned position
smoothed_q[in]contains the yield function and derivatives evaluated at (stress_params, intnl)
step_size[in]size of this (sub)strain increment
compute_full_tangent_operator[in]true if the full consistent tangent operator is needed, otherwise false
dvar_dtrial[out]dvar_dtrial[i][j] = d({stress_param[i],gaE})/d(trial_stress_param[j])

Definition at line 801 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

810 {
811  if (!_fe_problem.currentlyComputingJacobian())
812  return;
813 
814  if (!compute_full_tangent_operator)
815  return;
816 
817  if (elastic_only)
818  {
819  // no change to gaE, and all off-diag stuff remains unchanged from previous step
820  for (unsigned v = 0; v < _num_sp; ++v)
821  dvar_dtrial[v][v] += step_size;
822  return;
823  }
824 
825  const Real ga = gaE / _En;
826 
827  std::vector<std::vector<Real>> dintnl(_num_intnl, std::vector<Real>(_num_sp));
828  setIntnlDerivativesV(trial_stress_params, stress_params, intnl, dintnl);
829 
830  // rhs is described elsewhere, the following are changes in rhs wrt the trial_stress_param
831  // values
832  // In the following we use d(intnl)/d(trial variable) = - d(intnl)/d(variable)
833  std::vector<Real> rhs_cto((_num_sp + 1) * _num_sp);
834 
835  unsigned ind = 0;
836  for (unsigned a = 0; a < _num_sp; ++a)
837  {
838  // change in RHS[b] wrt changes in stress_param_trial[a]
839  for (unsigned b = 0; b < _num_sp; ++b)
840  {
841  if (a == b)
842  rhs_cto[ind] -= 1.0;
843  for (unsigned j = 0; j < _num_sp; ++j)
844  for (unsigned k = 0; k < _num_intnl; ++k)
845  rhs_cto[ind] -= ga * _Eij[b][j] * smoothed_q.d2g_di[j][k] * dintnl[k][a];
846  ind++;
847  }
848  // now b = _num_sp (that is, the yield function)
849  for (unsigned k = 0; k < _num_intnl; ++k)
850  rhs_cto[ind] -= smoothed_q.df_di[k] * dintnl[k][a];
851  ind++;
852  }
853 
854  // jac = d(-rhs)/d(var)
855  std::vector<double> jac((_num_sp + 1) * (_num_sp + 1));
856  dnRHSdVar(smoothed_q, dintnl, stress_params, gaE, jac);
857 
858  std::vector<int> ipiv(_num_sp + 1);
859  int info;
860  const int gesv_num_rhs = _num_sp + 1;
861  const int gesv_num_pq = _num_sp;
862  LAPACKgesv_(&gesv_num_rhs,
863  &gesv_num_pq,
864  &jac[0],
865  &gesv_num_rhs,
866  &ipiv[0],
867  &rhs_cto[0],
868  &gesv_num_rhs,
869  &info);
870  if (info != 0)
871  errorHandler("MultiParameterPlasticityStressUpdate: PETSC LAPACK gsev routine returned with "
872  "error code " +
873  Moose::stringify(info));
874 
875  ind = 0;
876  std::vector<std::vector<Real>> dvarn_dtrialn(_num_sp + 1, std::vector<Real>(_num_sp, 0.0));
877  for (unsigned spt = 0; spt < _num_sp; ++spt) // loop over trial stress-param variables
878  {
879  for (unsigned v = 0; v < _num_sp; ++v) // loop over variables in NR procedure
880  {
881  dvarn_dtrialn[v][spt] = rhs_cto[ind];
882  ind++;
883  }
884  // the final NR variable is gaE
885  dvarn_dtrialn[_num_sp][spt] = rhs_cto[ind];
886  ind++;
887  }
888 
889  const std::vector<std::vector<Real>> dvar_dtrial_old = dvar_dtrial;
890 
891  for (unsigned v = 0; v < _num_sp; ++v) // loop over variables in NR procedure
892  {
893  for (unsigned spt = 0; spt < _num_sp; ++spt) // loop over trial stress-param variables
894  {
895  dvar_dtrial[v][spt] = step_size * dvarn_dtrialn[v][spt];
896  for (unsigned a = 0; a < _num_sp; ++a)
897  dvar_dtrial[v][spt] += dvarn_dtrialn[v][a] * dvar_dtrial_old[a][spt];
898  }
899  }
900  // for gaE the formulae are a little different
901  const unsigned v = _num_sp;
902  for (unsigned spt = 0; spt < _num_sp; ++spt)
903  {
904  dvar_dtrial[v][spt] += step_size * dvarn_dtrialn[v][spt]; // note +=
905  for (unsigned a = 0; a < _num_sp; ++a)
906  dvar_dtrial[v][spt] += dvarn_dtrialn[v][a] * dvar_dtrial_old[a][spt];
907  }
908 }
const unsigned _num_intnl
Number of internal parameters.
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
virtual void setIntnlDerivativesV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl, std::vector< std::vector< Real >> &dintnl) const =0
Sets the derivatives of internal parameters, based on the trial values of stress_params, their current values, and the current values of the internal parameters.
virtual void errorHandler(const std::string &message) const
Performs any necessary cleaning-up, then throw MooseException(message)
void dnRHSdVar(const yieldAndFlow &smoothed_q, const std::vector< std::vector< Real >> &dintnl, const std::vector< Real > &stress_params, Real gaE, std::vector< double > &jac) const
Derivative of -RHS with respect to the stress_params and gaE, placed into an array ready for solving ...
const unsigned _num_sp
Number of stress parameters.
void MultiParameterPlasticityStressUpdate::errorHandler ( const std::string &  message) const
protectedvirtualinherited

Performs any necessary cleaning-up, then throw MooseException(message)

Parameters
messageThe message to using in MooseException

Definition at line 589 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::dVardTrial(), MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

590 {
591  throw MooseException(message);
592 }
void MultiParameterPlasticityStressUpdate::finalizeReturnProcess ( const RankTwoTensor &  rotation_increment)
protectedvirtualinherited

Derived classes may use this to perform calculations after the return-map process has completed successfully in stress_param space but before the returned stress tensor has been calculcated.

Parameters
rotation_increment[in]The large-strain rotation increment

Reimplemented in CappedDruckerPragerStressUpdate, CappedWeakPlaneStressUpdate, and CappedWeakInclinedPlaneStressUpdate.

Definition at line 600 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

602 {
603 }
void MultiParameterPlasticityStressUpdate::initializeReturnProcess ( )
protectedvirtualinherited

Derived classes may use this to perform calculations before any return-map process is performed, for instance, to initialize variables.

This is called at the very start of updateState, even before any checking for admissible stresses, etc, is performed

Reimplemented in CappedDruckerPragerStressUpdate, CappedWeakPlaneStressUpdate, and CappedWeakInclinedPlaneStressUpdate.

Definition at line 595 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

596 {
597 }
void TensileStressUpdate::initializeVarsV ( const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  intnl_old,
std::vector< Real > &  stress_params,
Real &  gaE,
std::vector< Real > &  intnl 
) const
overrideprotectedvirtual

Sets (stress_params, intnl) at "good guesses" of the solution to the Return-Map algorithm.

The purpose of these "good guesses" is to speed up the Newton-Raphson process by providing it with a good initial guess. Derived classes may choose to override this if their plastic models are easy enough to solve approximately. The default values, provided by this class, are simply gaE = 0, stress_params = trial_stress_params, that is, the "good guess" is just the trial point for this (sub)strain increment.

Parameters
trial_stress_params[in]The stress_params at the trial point
intnl_old[in]The internal parameters before applying the (sub)strain increment
stress_params[out]The "good guess" value of the stress_params
gaE[out]The "good guess" value of gaE
intnl[out]The "good guess" value of the internal parameters

Reimplemented from MultiParameterPlasticityStressUpdate.

Definition at line 165 of file TensileStressUpdate.C.

170 {
171  if (!_perfect_guess)
172  {
173  for (unsigned i = 0; i < _num_sp; ++i)
174  stress_params[i] = trial_stress_params[i];
175  gaE = 0.0;
176  }
177  else
178  {
179  const Real ts = tensile_strength(intnl_old[0]);
180  stress_params[2] = ts; // largest eigenvalue
181  stress_params[1] = std::min(stress_params[1], ts);
182  stress_params[0] = std::min(stress_params[0], ts);
183  gaE = trial_stress_params[2] - stress_params[2];
184  }
185  setIntnlValuesV(trial_stress_params, stress_params, intnl_old, intnl);
186 }
void setIntnlValuesV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &intnl) const override
Sets the internal parameters based on the trial values of stress_params, their current values...
virtual Real tensile_strength(const Real internal_param) const
tensile strength as a function of residual value, rate, and internal_param
const bool _perfect_guess
Whether to provide an estimate of the returned stress, based on perfect plasticity.
const unsigned _num_sp
Number of stress parameters.
void MultiParameterPlasticityStressUpdate::initQpStatefulProperties ( )
overrideprotectedvirtualinherited

Reimplemented in CappedWeakInclinedPlaneStressUpdate.

Definition at line 126 of file MultiParameterPlasticityStressUpdate.C.

Referenced by CappedWeakInclinedPlaneStressUpdate::initQpStatefulProperties().

127 {
128  _plastic_strain[_qp].zero();
129  _intnl[_qp].assign(_num_intnl, 0);
130  _yf[_qp].assign(_num_yf, 0);
131  _iter[_qp] = 0.0;
132  _linesearch_needed[_qp] = 0.0;
133 }
MaterialProperty< std::vector< Real > > & _yf
yield functions
const unsigned _num_intnl
Number of internal parameters.
MaterialProperty< std::vector< Real > > & _intnl
internal parameters
const unsigned _num_yf
Number of yield functions.
MaterialProperty< Real > & _iter
Number of Newton-Raphson iterations used in the return-map.
MaterialProperty< RankTwoTensor > & _plastic_strain
plastic strain
MaterialProperty< Real > & _linesearch_needed
Whether a line-search was needed in the latest Newton-Raphson process (1 if true, 0 otherwise) ...
Real MultiParameterPlasticityStressUpdate::ismoother ( Real  f_diff) const
protectedinherited

Smooths yield functions.

The returned value must be zero if abs(f_diff) >= _smoothing_tol and otherwise must satisfy, over -_smoothing_tol <= f_diff <= _smoothing_tol: (1) C2 (2) zero at f_diff = +/- _smoothing_tol (3) derivative is +/-0.5 at f_diff = +/- _smoothing_tol (4) derivative must be in [-0.5, 0.5] (5) second derivative is zero at f_diff = +/- _smoothing_tol (6) second derivative must be non-negative in order to ensure C2 differentiability and convexity of the smoothed yield surface.

Definition at line 457 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), MultiParameterPlasticityStressUpdate::smoothAllQuantities(), and MultiParameterPlasticityStressUpdate::yieldF().

458 {
459  if (std::abs(f_diff) >= _smoothing_tol)
460  return 0.0;
461  return -_smoothing_tol / M_PI * std::cos(0.5 * M_PI * f_diff / _smoothing_tol);
462 }
const Real _smoothing_tol
Smoothing tolerance: edges of the yield surface get smoothed by this amount.
int MultiParameterPlasticityStressUpdate::lineSearch ( Real &  res2,
std::vector< Real > &  stress_params,
Real &  gaE,
const std::vector< Real > &  trial_stress_params,
yieldAndFlow smoothed_q,
const std::vector< Real > &  intnl_ok,
std::vector< Real > &  intnl,
std::vector< Real > &  rhs,
Real &  linesearch_needed 
) const
protectedinherited

Performs a line-search to find stress_params and gaE Upon entry:

  • rhs contains the solution to the Newton-Raphson (ie nrStep should have been called). If a full Newton step is used then stress_params[:] += rhs[0:_num_sp-1] and gaE += rhs[_num_sp]
  • res2 contains the residual-squared before applying any of solution
  • stress_params contains the stress_params before applying any of the solution
  • gaE contains gaE before applying any of the solution (that is contained in rhs) Upon exit:
  • stress_params will be the stress_params after applying the solution
  • gaE will be the stress_params after applying the solution
  • rhs will contain the updated rhs values (after applying the solution) ready for the next Newton-Raphson step,
  • res2 will be the residual-squared after applying the solution
  • intnl will contain the internal variables corresponding to the return from trial_stress_params to stress_params (and starting from intnl_ok)
  • linesearch_needed will be 1.0 if a linesearch was needed
  • smoothed_q will contain the value of the yield function and its derivatives, etc, at (stress_params, intnl)
    Parameters
    res2[in,out]the residual-squared, both as an input and output
    stress_params[in,out]Upon input the value of the stress_params before the current Newton-Raphson process was initiated. Upon exit this will hold the values coming from the line search.
    trial_stress_params[in]Trial value for the stress_params for this (sub)strain increment
    gaE[in,out]Upon input the value of gaE before the current Newton-Raphson iteration was initiated. Upon exit this will hold the value coming from the line-search
    smoothed_q[in,out]Upon input, the value of the smoothed yield function and derivatives at the prior-to-Newton configuration. Upon exit this is evaluated at the new (stress_params, intnl)
    intnl_ok[in]The value of the internal parameters from the start of this (sub)strain increment
    intnl[in,out]The value of the internal parameters after the line-search has converged
    rhs[in,out]Upon entry this contains the solution to the Newton-Raphson. Upon exit this contains the updated rhs values
    Returns
    0 if successful, 1 otherwise

Definition at line 481 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

490 {
491  const Real res2_old = res2;
492  const std::vector<Real> sp_params_old = stress_params;
493  const Real gaE_old = gaE;
494  const std::vector<Real> delta_nr_params = rhs;
495 
496  Real lam = 1.0; // line-search parameter
497  const Real lam_min = 1E-10; // minimum value of lam allowed
498  const Real slope = -2.0 * res2_old; // "Numerical Recipes" uses -b*A*x, in order to check for
499  // roundoff, but i hope the nrStep would warn if there were
500  // problems
501  Real tmp_lam; // cached value of lam used in quadratic & cubic line search
502  Real f2 = res2_old; // cached value of f = residual2 used in the cubic in the line search
503  Real lam2 = lam; // cached value of lam used in the cubic in the line search
504 
505  while (true)
506  {
507  // update variables using the current line-search parameter
508  for (unsigned i = 0; i < _num_sp; ++i)
509  stress_params[i] = sp_params_old[i] + lam * delta_nr_params[i];
510  gaE = gaE_old + lam * delta_nr_params[_num_sp];
511 
512  // and internal parameters
513  setIntnlValuesV(trial_stress_params, stress_params, intnl_ok, intnl);
514 
515  smoothed_q = smoothAllQuantities(stress_params, intnl);
516 
517  // update rhs for next-time through
518  calculateRHS(trial_stress_params, stress_params, gaE, smoothed_q, rhs);
519  res2 = calculateRes2(rhs);
520 
521  // do the line-search
522  if (res2 < res2_old + 1E-4 * lam * slope)
523  break;
524  else if (lam < lam_min)
525  return 1;
526  else if (lam == 1.0)
527  {
528  // model as a quadratic
529  tmp_lam = -0.5 * slope / (res2 - res2_old - slope);
530  }
531  else
532  {
533  // model as a cubic
534  const Real rhs1 = res2 - res2_old - lam * slope;
535  const Real rhs2 = f2 - res2_old - lam2 * slope;
536  const Real a = (rhs1 / Utility::pow<2>(lam) - rhs2 / Utility::pow<2>(lam2)) / (lam - lam2);
537  const Real b =
538  (-lam2 * rhs1 / Utility::pow<2>(lam) + lam * rhs2 / Utility::pow<2>(lam2)) / (lam - lam2);
539  if (a == 0.0)
540  tmp_lam = -slope / (2.0 * b);
541  else
542  {
543  const Real disc = Utility::pow<2>(b) - 3.0 * a * slope;
544  if (disc < 0)
545  tmp_lam = 0.5 * lam;
546  else if (b <= 0)
547  tmp_lam = (-b + std::sqrt(disc)) / (3.0 * a);
548  else
549  tmp_lam = -slope / (b + std::sqrt(disc));
550  }
551  if (tmp_lam > 0.5 * lam)
552  tmp_lam = 0.5 * lam;
553  }
554  lam2 = lam;
555  f2 = res2;
556  lam = std::max(tmp_lam, 0.1 * lam);
557  }
558 
559  if (lam < 1.0)
560  linesearch_needed = 1.0;
561  return 0;
562 }
void calculateRHS(const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, Real gaE, const yieldAndFlow &smoothed_q, std::vector< Real > &rhs) const
Calculates the RHS in the following 0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, j] * dg/dS[j] 0 = rhs[...
yieldAndFlow smoothAllQuantities(const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
Calculates all yield functions and derivatives, and then performs the smoothing scheme.
Real calculateRes2(const std::vector< Real > &rhs) const
Calculates the residual-squared for the Newton-Raphson + line-search.
virtual void setIntnlValuesV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &intnl) const =0
Sets the internal parameters based on the trial values of stress_params, their current values...
const unsigned _num_sp
Number of stress parameters.
int MultiParameterPlasticityStressUpdate::nrStep ( const yieldAndFlow smoothed_q,
const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  stress_params,
const std::vector< Real > &  intnl,
Real  gaE,
std::vector< Real > &  rhs 
) const
protectedinherited

Performs a Newton-Raphson step to attempt to zero rhs Upon return, rhs will contain the solution.

Parameters
smoothed_q[in]The value of the smoothed yield function and derivatives prior to this Newton-Raphson step
trial_stress_params[in]Trial value for the stress_params for this (sub)strain increment
stress_params[in]The current value of the stress_params
intnl[in]The current value of the internal parameters
gaE[in]The current value of gaE
rhs[in,out]Upon entry, the rhs to zero using Newton-Raphson. Upon exit, the solution to the Newton-Raphson problem
Returns
0 if successful, 1 otherwise

Definition at line 565 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

571 {
572  std::vector<std::vector<Real>> dintnl(_num_intnl, std::vector<Real>(_num_sp));
573  setIntnlDerivativesV(trial_stress_params, stress_params, intnl, dintnl);
574 
575  std::vector<double> jac((_num_sp + 1) * (_num_sp + 1));
576  dnRHSdVar(smoothed_q, dintnl, stress_params, gaE, jac);
577 
578  // use LAPACK to solve the linear system
579  const int nrhs = 1;
580  std::vector<int> ipiv(_num_sp + 1);
581  int info;
582  const int gesv_num_rhs = _num_sp + 1;
583  LAPACKgesv_(
584  &gesv_num_rhs, &nrhs, &jac[0], &gesv_num_rhs, &ipiv[0], &rhs[0], &gesv_num_rhs, &info);
585  return info;
586 }
const unsigned _num_intnl
Number of internal parameters.
virtual void setIntnlDerivativesV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl, std::vector< std::vector< Real >> &dintnl) const =0
Sets the derivatives of internal parameters, based on the trial values of stress_params, their current values, and the current values of the internal parameters.
void dnRHSdVar(const yieldAndFlow &smoothed_q, const std::vector< std::vector< Real >> &dintnl, const std::vector< Real > &stress_params, Real gaE, std::vector< double > &jac) const
Derivative of -RHS with respect to the stress_params and gaE, placed into an array ready for solving ...
const unsigned _num_sp
Number of stress parameters.
bool MultiParameterPlasticityStressUpdate::precisionLoss ( const std::vector< Real > &  solution,
const std::vector< Real > &  stress_params,
Real  gaE 
) const
protectedinherited

Check whether precision loss has occurred.

Parameters
[in]solutionThe solution to the Newton-Raphson system
[in]stress_paramsThe currect values of the stress_params for this (sub)strain increment
[in]gaEThe currenct value of gaE for this (sub)strain increment
Returns
true if precision loss has occurred

Definition at line 911 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

914 {
915  if (std::abs(solution[_num_sp]) > 1E-13 * std::abs(gaE))
916  return false;
917  for (unsigned i = 0; i < _num_sp; ++i)
918  if (std::abs(solution[i]) > 1E-13 * std::abs(stress_params[i]))
919  return false;
920  return true;
921 }
const unsigned _num_sp
Number of stress parameters.
void TensileStressUpdate::preReturnMapV ( const std::vector< Real > &  trial_stress_params,
const RankTwoTensor &  stress_trial,
const std::vector< Real > &  intnl_old,
const std::vector< Real > &  yf,
const RankFourTensor &  Eijkl 
)
overrideprotectedvirtual

Derived classes may employ this function to record stuff or do other computations prior to the return-mapping algorithm.

We know that (trial_stress_params, intnl_old) is inadmissible when this is called

Parameters
trial_stress_params[in]The trial values of the stress parameters
stress_trial[in]Trial stress tensor
intnl_old[in]Old value of the internal parameters.
yf[in]The yield functions at (p_trial, q_trial, intnl_old)
Eijkl[in]The elasticity tensor

Reimplemented from MultiParameterPlasticityStressUpdate.

Definition at line 63 of file TensileStressUpdate.C.

68 {
69  std::vector<Real> eigvals;
70  stress_trial.symmetricEigenvaluesEigenvectors(eigvals, _eigvecs);
71 }
RankTwoTensor _eigvecs
Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to s...
void MultiParameterPlasticityStressUpdate::propagateQpStatefulProperties ( )
overrideprotectedvirtualinherited

If updateState is not called during a timestep, this will be.

This method allows derived classes to set internal parameters from their Old values, for instance

Reimplemented from StressUpdateBase.

Definition at line 136 of file MultiParameterPlasticityStressUpdate.C.

137 {
139  for (unsigned i = 0; i < _num_intnl; ++i)
140  _intnl[_qp][i] = _intnl_old[_qp][i];
141 }
const unsigned _num_intnl
Number of internal parameters.
MaterialProperty< std::vector< Real > > & _intnl
internal parameters
const MaterialProperty< std::vector< Real > > & _intnl_old
old values of internal parameters
MaterialProperty< RankTwoTensor > & _plastic_strain
plastic strain
const MaterialProperty< RankTwoTensor > & _plastic_strain_old
Old value of plastic strain.
bool TensileStressUpdate::requiresIsotropicTensor ( )
inlineoverridevirtual

Does the model require the elasticity tensor to be isotropic?

Implements StressUpdateBase.

Definition at line 30 of file TensileStressUpdate.h.

30 { return true; }
void StressUpdateBase::resetProperties ( )
inlinefinalinherited

Definition at line 93 of file StressUpdateBase.h.

93 {}
void StressUpdateBase::resetQpProperties ( )
inlinefinalinherited

Retained as empty methods to avoid a warning from Material.C in framework. These methods are unused in all inheriting classes and should not be overwritten.

Definition at line 92 of file StressUpdateBase.h.

92 {}
void TensileStressUpdate::setEffectiveElasticity ( const RankFourTensor &  Eijkl)
overrideprotectedvirtual

Sets _Eij and _En and _Cij.

Implements MultiParameterPlasticityStressUpdate.

Definition at line 147 of file TensileStressUpdate.C.

148 {
149  // Eijkl is required to be isotropic, so we can use the
150  // frame where stress is diagonal
151  for (unsigned a = 0; a < _num_sp; ++a)
152  for (unsigned b = 0; b < _num_sp; ++b)
153  _Eij[a][b] = Eijkl(a, a, b, b);
154  _En = _Eij[2][2];
155  const Real denom = _Eij[0][0] * (_Eij[0][0] + _Eij[0][1]) - 2 * Utility::pow<2>(_Eij[0][1]);
156  for (unsigned a = 0; a < _num_sp; ++a)
157  {
158  _Cij[a][a] = (_Eij[0][0] + _Eij[0][1]) / denom;
159  for (unsigned b = 0; b < a; ++b)
160  _Cij[a][b] = _Cij[b][a] = -_Eij[0][1] / denom;
161  }
162 }
std::vector< std::vector< Real > > _Cij
_Cij[i, j] * _Eij[j, k] = 1 iff j == k
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
const unsigned _num_sp
Number of stress parameters.
void MultiParameterPlasticityStressUpdate::setInelasticStrainIncrementAfterReturn ( const RankTwoTensor &  stress_trial,
Real  gaE,
const yieldAndFlow smoothed_q,
const RankFourTensor &  elasticity_tensor,
const RankTwoTensor &  returned_stress,
RankTwoTensor &  inelastic_strain_increment 
) const
protectedvirtualinherited

Sets inelastic strain increment from the returned configuration This is called after the return-map process has completed successfully in stress_param space, just after finalizeReturnProcess has been called.

Derived classes may override this function

Parameters
stress_trial[in]The trial value of stress
gaE[in]The value of gaE after the return-map process has completed successfully
smoothed_q[in]Holds the current value of yield function and derivatives evaluated at the returned configuration
elasticity_tensor[in]The elasticity tensor
returned_stress[in]The stress after the return-map process
inelastic_strain_increment[out]The inelastic strain increment resulting from this return-map

Reimplemented in TwoParameterPlasticityStressUpdate.

Definition at line 714 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

721 {
722  const std::vector<RankTwoTensor> dsp_dstress = dstress_param_dstress(returned_stress);
723  inelastic_strain_increment = RankTwoTensor();
724  for (unsigned i = 0; i < _num_sp; ++i)
725  inelastic_strain_increment += smoothed_q.dg[i] * dsp_dstress[i];
726  inelastic_strain_increment *= gaE / _En;
727 }
virtual std::vector< RankTwoTensor > dstress_param_dstress(const RankTwoTensor &stress) const =0
d(stress_param[i])/d(stress) at given stress
const unsigned _num_sp
Number of stress parameters.
void TensileStressUpdate::setIntnlDerivativesV ( const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  current_stress_params,
const std::vector< Real > &  intnl,
std::vector< std::vector< Real >> &  dintnl 
) const
overrideprotectedvirtual

Sets the derivatives of internal parameters, based on the trial values of stress_params, their current values, and the current values of the internal parameters.

Derived classes must override this.

Parameters
trial_stress_params[in]The trial stress parameters
current_stress_params[in]The current stress parameters
intnl[in]The current value of the internal parameters
dintnl[out]The derivatives dintnl[i][j] = d(intnl[i])/d(stress_param j)

Implements MultiParameterPlasticityStressUpdate.

Definition at line 198 of file TensileStressUpdate.C.

202 {
203  dintnl[0][0] = 0.0;
204  dintnl[0][1] = 0.0;
205  dintnl[0][2] = -1.0 / _Eij[2][2];
206 }
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
void TensileStressUpdate::setIntnlValuesV ( const std::vector< Real > &  trial_stress_params,
const std::vector< Real > &  current_stress_params,
const std::vector< Real > &  intnl_old,
std::vector< Real > &  intnl 
) const
overrideprotectedvirtual

Sets the internal parameters based on the trial values of stress_params, their current values, and the old values of the internal parameters.

Derived classes must override this.

Parameters
trial_stress_params[in]The trial stress parameters (eg trial_p and trial_q)
current_stress_params[in]The current stress parameters (eg p and q)
intnl_old[out]Old value of internal parameters
intnl[out]The value of internal parameters to be set

Implements MultiParameterPlasticityStressUpdate.

Definition at line 189 of file TensileStressUpdate.C.

Referenced by initializeVarsV().

193 {
194  intnl[0] = intnl_old[0] + (trial_stress_params[2] - current_stress_params[2]) / _Eij[2][2];
195 }
std::vector< std::vector< Real > > _Eij
E[i, j] in the system of equations to be solved.
void StressUpdateBase::setQp ( unsigned int  qp)
inherited

Sets the value of the global variable _qp for inheriting classes.

Definition at line 30 of file StressUpdateBase.C.

31 {
32  _qp = qp;
33 }
void TensileStressUpdate::setStressAfterReturnV ( const RankTwoTensor &  stress_trial,
const std::vector< Real > &  stress_params,
Real  gaE,
const std::vector< Real > &  intnl,
const yieldAndFlow smoothed_q,
const RankFourTensor &  Eijkl,
RankTwoTensor &  stress 
) const
overrideprotectedvirtual

Sets stress from the admissible parameters.

This is called after the return-map process has completed successfully in stress_param space, just after finalizeReturnProcess has been called. Derived classes must override this function

Parameters
stress_trial[in]The trial value of stress
stress_params[in]The value of the stress_params after the return-map process has completed successfully
gaE[in]The value of gaE after the return-map process has completed successfully
intnl[in]The value of the internal parameters after the return-map process has completed successfully
smoothed_q[in]Holds the current value of yield function and derivatives evaluated at the returned state
Eijkl[in]The elasticity tensor
stress[out]The returned value of the stress tensor

Implements MultiParameterPlasticityStressUpdate.

Definition at line 74 of file TensileStressUpdate.C.

81 {
82  // form the diagonal stress
83  stress = RankTwoTensor(stress_params[0], stress_params[1], stress_params[2], 0.0, 0.0, 0.0);
84  // rotate to the original frame
85  stress = _eigvecs * stress * (_eigvecs.transpose());
86 }
RankTwoTensor _eigvecs
Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to s...
MultiParameterPlasticityStressUpdate::yieldAndFlow MultiParameterPlasticityStressUpdate::smoothAllQuantities ( const std::vector< Real > &  stress_params,
const std::vector< Real > &  intnl 
) const
protectedinherited

Calculates all yield functions and derivatives, and then performs the smoothing scheme.

Parameters
stress_params[in]The stress parameters (eg stress_params[0] = stress_zz and stress_params[1] = sqrt(stress_zx^2 + stress_zy^2))
intnl[in]Internal parameters
Returns
The smoothed yield function and derivatives

Definition at line 373 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::lineSearch(), MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

375 {
376  std::vector<yieldAndFlow> all_q(_num_yf, yieldAndFlow(_num_sp, _num_intnl));
377  computeAllQV(stress_params, intnl, all_q);
378 
379  /* This routine holds the key to my smoothing strategy. It
380  * may be proved that this smoothing strategy produces a
381  * yield surface that is both C2 differentiable and convex,
382  * assuming the individual yield functions are C2 and
383  * convex too.
384  * Of course all the derivatives must also be smoothed.
385  * Also, I assume that d(flow potential)/dstress gets smoothed
386  * by the Yield Function (which produces a C2 flow potential).
387  * See the line identified in the loop below.
388  * Only time will tell whether this is a good strategy, but it
389  * works well in all tests so far. Convexity is irrelevant
390  * for the non-associated case, but at least the return-map
391  * problem should always have a unique solution.
392  * For two yield functions+flows, labelled 1 and 2, we
393  * should have
394  * d(g1 - g2) . d(f1 - f2) >= 0
395  * If not then the return-map problem for even the
396  * multi-surface plasticity with no smoothing won't have a
397  * unique solution. If the multi-surface plasticity has
398  * a unique solution then the smoothed version defined
399  * below will too.
400  */
401 
402  // res_f is the index that contains the smoothed yieldAndFlow
403  std::size_t res_f = 0;
404 
405  for (std::size_t a = 1; a < all_q.size(); ++a)
406  {
407  if (all_q[res_f].f >= all_q[a].f + _smoothing_tol)
408  // no smoothing is needed: res_f is already indexes the largest yield function
409  continue;
410  else if (all_q[a].f >= all_q[res_f].f + _smoothing_tol)
411  {
412  // no smoothing is needed, and res_f needs to index to all_q[a]
413  res_f = a;
414  continue;
415  }
416  else
417  {
418  // smoothing is required
419  const Real f_diff = all_q[res_f].f - all_q[a].f;
420  const Real ism = ismoother(f_diff);
421  const Real sm = smoother(f_diff);
422  const Real dsm = dsmoother(f_diff);
423  // we want: all_q[res_f].f = 0.5 * all_q[res_f].f + all_q[a].f + _smoothing_tol) + ism,
424  // but we have to do the derivatives first
425  for (unsigned i = 0; i < _num_sp; ++i)
426  {
427  for (unsigned j = 0; j < _num_sp; ++j)
428  all_q[res_f].d2g[i][j] =
429  0.5 * (all_q[res_f].d2g[i][j] + all_q[a].d2g[i][j]) +
430  dsm * (all_q[res_f].df[j] - all_q[a].df[j]) * (all_q[res_f].dg[i] - all_q[a].dg[i]) +
431  sm * (all_q[res_f].d2g[i][j] - all_q[a].d2g[i][j]);
432  for (unsigned j = 0; j < _num_intnl; ++j)
433  all_q[res_f].d2g_di[i][j] = 0.5 * (all_q[res_f].d2g_di[i][j] + all_q[a].d2g_di[i][j]) +
434  dsm * (all_q[res_f].df_di[j] - all_q[a].df_di[j]) *
435  (all_q[res_f].dg[i] - all_q[a].dg[i]) +
436  sm * (all_q[res_f].d2g_di[i][j] - all_q[a].d2g_di[i][j]);
437  }
438  for (unsigned i = 0; i < _num_sp; ++i)
439  {
440  all_q[res_f].df[i] = 0.5 * (all_q[res_f].df[i] + all_q[a].df[i]) +
441  sm * (all_q[res_f].df[i] - all_q[a].df[i]);
442  // whether the following (smoothing g with f's smoother) is a good strategy remains to be
443  // seen...
444  all_q[res_f].dg[i] = 0.5 * (all_q[res_f].dg[i] + all_q[a].dg[i]) +
445  sm * (all_q[res_f].dg[i] - all_q[a].dg[i]);
446  }
447  for (unsigned i = 0; i < _num_intnl; ++i)
448  all_q[res_f].df_di[i] = 0.5 * (all_q[res_f].df_di[i] + all_q[a].df_di[i]) +
449  sm * (all_q[res_f].df_di[i] - all_q[a].df_di[i]);
450  all_q[res_f].f = 0.5 * (all_q[res_f].f + all_q[a].f + _smoothing_tol) + ism;
451  }
452  }
453  return all_q[res_f];
454 }
virtual void computeAllQV(const std::vector< Real > &stress_params, const std::vector< Real > &intnl, std::vector< yieldAndFlow > &all_q) const =0
Completely fills all_q with correct values.
Real smoother(Real f_diff) const
Derivative of ismoother.
const unsigned _num_intnl
Number of internal parameters.
const unsigned _num_yf
Number of yield functions.
Real ismoother(Real f_diff) const
Smooths yield functions.
const Real _smoothing_tol
Smoothing tolerance: edges of the yield surface get smoothed by this amount.
Real dsmoother(Real f_diff) const
Derivative of smoother.
const unsigned _num_sp
Number of stress parameters.
Real MultiParameterPlasticityStressUpdate::smoother ( Real  f_diff) const
protectedinherited

Derivative of ismoother.

Definition at line 465 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::smoothAllQuantities().

466 {
467  if (std::abs(f_diff) >= _smoothing_tol)
468  return 0.0;
469  return 0.5 * std::sin(f_diff * M_PI * 0.5 / _smoothing_tol);
470 }
const Real _smoothing_tol
Smoothing tolerance: edges of the yield surface get smoothed by this amount.
Real TensileStressUpdate::tensile_strength ( const Real  internal_param) const
protectedvirtual

tensile strength as a function of residual value, rate, and internal_param

Definition at line 209 of file TensileStressUpdate.C.

Referenced by computeAllQV(), initializeVarsV(), and yieldFunctionValuesV().

210 {
211  return _strength.value(internal_param);
212 }
const TensorMechanicsHardeningModel & _strength
Hardening model for tensile strength.
virtual Real value(Real intnl) const
void MultiParameterPlasticityStressUpdate::updateState ( RankTwoTensor &  strain_increment,
RankTwoTensor &  inelastic_strain_increment,
const RankTwoTensor &  rotation_increment,
RankTwoTensor &  stress_new,
const RankTwoTensor &  stress_old,
const RankFourTensor &  elasticity_tensor,
const RankTwoTensor &  elastic_strain_old,
bool  compute_full_tangent_operator,
RankFourTensor &  tangent_operator 
)
overrideprotectedvirtualinherited

Given a strain increment that results in a trial stress, perform some procedure (such as an iterative return-mapping process) to produce an admissible stress, an elastic strain increment and an inelastic strain increment.

If _fe_problem.currentlyComputingJacobian() = true, then updateState also computes d(stress)/d(strain) (or some approximation to it).

This method is called by ComputeMultipleInelasticStress. This method is pure virutal: all inheriting classes must overwrite this method.

Parameters
strain_incrementUpon input: the strain increment. Upon output: the elastic strain increment
inelastic_strain_incrementThe inelastic_strain resulting from the interative procedure
rotation_incrementThe finite-strain rotation increment
stress_newUpon input: the trial stress that results from applying strain_increment as an elastic strain. Upon output: the admissible stress
stress_oldThe old value of stress
elasticity_tensorThe elasticity tensor
compute_full_tangent_operatorThe calling routine would like the full consistent tangent operator to be placed in tangent_operator, if possible. This is irrelevant if _fe_problem.currentlyComputingJacobian() = false
tangent_operatord(stress)/d(strain), or some approximation to it If compute_full_tangent_operator=false, then tangent_operator=elasticity_tensor is an appropriate choice. tangent_operator is only computed if _fe_problem.currentlyComputingJacobian() = true

Implements StressUpdateBase.

Definition at line 144 of file MultiParameterPlasticityStressUpdate.C.

153 {
155 
156  if (_t_step >= 2)
157  _step_one = false;
158 
159  // initially assume an elastic deformation
160  std::copy(_intnl_old[_qp].begin(), _intnl_old[_qp].end(), _intnl[_qp].begin());
161  _iter[_qp] = 0.0;
162  _linesearch_needed[_qp] = 0.0;
163 
164  computeStressParams(stress_new, _trial_sp);
166 
167  if (yieldF(_yf[_qp]) <= _f_tol)
168  {
170  inelastic_strain_increment.zero();
171  if (_fe_problem.currentlyComputingJacobian())
172  tangent_operator = elasticity_tensor;
173  return;
174  }
175 
176  _stress_trial = stress_new;
177  /* The trial stress must be inadmissible
178  * so we need to return to the yield surface. The following
179  * equations must be satisfied.
180  *
181  * 0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, i] * dg/dS[i]
182  * 0 = rhs[1] = S[1] - S[1]^trial + ga * E[1, i] * dg/dS[i]
183  * ...
184  * 0 = rhs[N-1] = S[N-1] - S[N-1]^trial + ga * E[N-1, i] * dg/dS[i]
185  * 0 = rhs[N] = f(S, intnl)
186  *
187  * as well as equations defining intnl parameters as functions of
188  * stress_params, trial_stress_params and intnl_old
189  *
190  * The unknowns are S[0], ..., S[N-1], gaE, and the intnl parameters.
191  * Here gaE = ga * _En (the _En serves to make gaE similar magnitude to S)
192  * I find it convenient to solve the first N+1 equations for p, q and gaE,
193  * while substituting the "intnl parameters" equations into these during the solve process
194  */
195 
196  for (auto & deriv : _dvar_dtrial)
197  deriv.assign(_num_sp, 0.0);
198 
199  preReturnMapV(_trial_sp, stress_new, _intnl_old[_qp], _yf[_qp], elasticity_tensor);
200 
201  setEffectiveElasticity(elasticity_tensor);
202 
203  if (_step_one)
204  std::copy(_definitely_ok_sp.begin(), _definitely_ok_sp.end(), _ok_sp.begin());
205  else
206  computeStressParams(stress_old, _ok_sp);
207  std::copy(_intnl_old[_qp].begin(), _intnl_old[_qp].end(), _ok_intnl.begin());
208 
209  // Return-map problem: must apply the following changes in stress_params,
210  // and find the returned stress_params and gaE
211  for (unsigned i = 0; i < _num_sp; ++i)
212  _del_stress_params[i] = _trial_sp[i] - _ok_sp[i];
213 
214  Real step_taken = 0.0; // amount of del_stress_params that we've applied and the return-map
215  // problem has succeeded
216  Real step_size = 1.0; // potentially can apply del_stress_params in substeps
217  Real gaE_total = 0.0;
218 
219  // current values of the yield function, derivatives, etc
220  yieldAndFlow smoothed_q;
221 
222  // In the following sub-stepping procedure it is possible that
223  // the last step is an elastic step, and therefore smoothed_q won't
224  // be computed on the last step, so we have to compute it.
225  bool smoothed_q_calculated = false;
226 
227  while (step_taken < 1.0 && step_size >= _min_step_size)
228  {
229  if (1.0 - step_taken < step_size)
230  // prevent over-shoots of substepping
231  step_size = 1.0 - step_taken;
232 
233  // trial variables in terms of admissible variables
234  for (unsigned i = 0; i < _num_sp; ++i)
235  _trial_sp[i] = _ok_sp[i] + step_size * _del_stress_params[i];
236 
237  // initialize variables that are to be found via Newton-Raphson
239  Real gaE = 0.0;
240 
241  // flags indicating failure of Newton-Raphson and line-search
242  int nr_failure = 0;
243  int ls_failure = 0;
244 
245  // NR iterations taken in this substep
246  unsigned step_iter = 0;
247 
248  // The residual-squared for the line-search
249  Real res2 = 0.0;
250 
251  if (step_size < 1.0 && yieldF(_trial_sp, _ok_intnl) <= _f_tol)
252  // This is an elastic step
253  // The "step_size < 1.0" in above condition is for efficiency: we definitely
254  // know that this is a plastic step if step_size = 1.0
255  smoothed_q_calculated = false;
256  else
257  {
258  // this is a plastic step
259 
260  // initialize current_sp, gaE and current_intnl based on the non-smoothed situation
262  // and find the smoothed yield function, flow potential and derivatives
264  smoothed_q_calculated = true;
265  calculateRHS(_trial_sp, _current_sp, gaE, smoothed_q, _rhs);
266  res2 = calculateRes2(_rhs);
267 
268  // Perform a Newton-Raphson with linesearch to get current_sp, gaE, and also smoothed_q
269  while (res2 > _f_tol2 && step_iter < _max_nr_its && nr_failure == 0 && ls_failure == 0)
270  {
271  // solve the linear system and store the answer (the "updates") in rhs
272  nr_failure = nrStep(smoothed_q, _trial_sp, _current_sp, _current_intnl, gaE, _rhs);
273  if (nr_failure != 0)
274  break;
275 
276  // handle precision loss
277  if (precisionLoss(_rhs, _current_sp, gaE))
278  {
280  {
281  Moose::err << "MultiParameterPlasticityStressUpdate: precision-loss in element "
282  << _current_elem->id() << " quadpoint=" << _qp << ". Stress_params =";
283  for (unsigned i = 0; i < _num_sp; ++i)
284  Moose::err << " " << _current_sp[i];
285  Moose::err << " gaE = " << gaE << "\n";
286  }
287  res2 = 0.0;
288  break;
289  }
290 
291  // apply (parts of) the updates, re-calculate smoothed_q, and res2
292  ls_failure = lineSearch(res2,
293  _current_sp,
294  gaE,
295  _trial_sp,
296  smoothed_q,
297  _ok_intnl,
299  _rhs,
300  _linesearch_needed[_qp]);
301  step_iter++;
302  }
303  }
304 
305  if (res2 <= _f_tol2 && step_iter < _max_nr_its && nr_failure == 0 && ls_failure == 0 &&
306  gaE >= 0.0)
307  {
308  // this Newton-Raphson worked fine, or this was an elastic step
309  std::copy(_current_sp.begin(), _current_sp.end(), _ok_sp.begin());
310  gaE_total += gaE;
311  step_taken += step_size;
313  std::copy(_intnl[_qp].begin(), _intnl[_qp].end(), _ok_intnl.begin());
314  // calculate dp/dp_trial, dp/dq_trial, etc, for Jacobian
315  dVardTrial(!smoothed_q_calculated,
316  _trial_sp,
317  _ok_sp,
318  gaE,
319  _ok_intnl,
320  smoothed_q,
321  step_size,
322  compute_full_tangent_operator,
323  _dvar_dtrial);
324  if (static_cast<Real>(step_iter) > _iter[_qp])
325  _iter[_qp] = static_cast<Real>(step_iter);
326  step_size *= 1.1;
327  }
328  else
329  {
330  // Newton-Raphson + line-search process failed
331  step_size *= 0.5;
332  }
333  }
334 
335  if (step_size < _min_step_size)
336  errorHandler("MultiParameterPlasticityStressUpdate: Minimum step-size violated");
337 
338  // success!
339  finalizeReturnProcess(rotation_increment);
340  yieldFunctionValuesV(_ok_sp, _intnl[_qp], _yf[_qp]);
341 
342  if (!smoothed_q_calculated)
343  smoothed_q = smoothAllQuantities(_ok_sp, _intnl[_qp]);
344 
346  _stress_trial, _ok_sp, gaE_total, _intnl[_qp], smoothed_q, elasticity_tensor, stress_new);
347 
349  gaE_total,
350  smoothed_q,
351  elasticity_tensor,
352  stress_new,
353  inelastic_strain_increment);
354 
355  strain_increment = strain_increment - inelastic_strain_increment;
356  _plastic_strain[_qp] = _plastic_strain_old[_qp] + inelastic_strain_increment;
357 
358  if (_fe_problem.currentlyComputingJacobian())
359  // for efficiency, do not compute the tangent operator if not currently computing Jacobian
361  _trial_sp,
362  stress_new,
363  _ok_sp,
364  gaE_total,
365  smoothed_q,
366  elasticity_tensor,
367  compute_full_tangent_operator,
368  _dvar_dtrial,
369  tangent_operator);
370 }
int nrStep(const yieldAndFlow &smoothed_q, const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, const std::vector< Real > &intnl, Real gaE, std::vector< Real > &rhs) const
Performs a Newton-Raphson step to attempt to zero rhs Upon return, rhs will contain the solution...
virtual void initializeVarsV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &stress_params, Real &gaE, std::vector< Real > &intnl) const
Sets (stress_params, intnl) at "good guesses" of the solution to the Return-Map algorithm.
MaterialProperty< std::vector< Real > > & _yf
yield functions
std::vector< Real > _trial_sp
"Trial" value of stress_params that initializes the return-map process This is derived from stress = ...
virtual void setEffectiveElasticity(const RankFourTensor &Eijkl)=0
Sets _Eij and _En and _Cij.
const bool _warn_about_precision_loss
Output a warning message if precision loss is encountered during the return-map process.
void calculateRHS(const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, Real gaE, const yieldAndFlow &smoothed_q, std::vector< Real > &rhs) const
Calculates the RHS in the following 0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, j] * dg/dS[j] 0 = rhs[...
virtual void consistentTangentOperatorV(const RankTwoTensor &stress_trial, const std::vector< Real > &trial_stress_params, const RankTwoTensor &stress, const std::vector< Real > &stress_params, Real gaE, const yieldAndFlow &smoothed_q, const RankFourTensor &Eijkl, bool compute_full_tangent_operator, const std::vector< std::vector< Real >> &dvar_dtrial, RankFourTensor &cto)
Calculates the consistent tangent operator.
virtual void setStressAfterReturnV(const RankTwoTensor &stress_trial, const std::vector< Real > &stress_params, Real gaE, const std::vector< Real > &intnl, const yieldAndFlow &smoothed_q, const RankFourTensor &Eijkl, RankTwoTensor &stress) const =0
Sets stress from the admissible parameters.
virtual void yieldFunctionValuesV(const std::vector< Real > &stress_params, const std::vector< Real > &intnl, std::vector< Real > &yf) const =0
Computes the values of the yield functions, given stress_params and intnl parameters.
std::vector< Real > _ok_intnl
The state (ok_sp, ok_intnl) is known to be admissible.
const Real _f_tol2
Square of the yield-function tolerance.
const Real _min_step_size
In order to help the Newton-Raphson procedure, the applied strain increment may be applied in sub-inc...
MaterialProperty< std::vector< Real > > & _intnl
internal parameters
const Real _f_tol
The yield-function tolerance.
int lineSearch(Real &res2, std::vector< Real > &stress_params, Real &gaE, const std::vector< Real > &trial_stress_params, yieldAndFlow &smoothed_q, const std::vector< Real > &intnl_ok, std::vector< Real > &intnl, std::vector< Real > &rhs, Real &linesearch_needed) const
Performs a line-search to find stress_params and gaE Upon entry:
const std::vector< Real > _definitely_ok_sp
An admissible value of stress_params at the initial time.
const MaterialProperty< std::vector< Real > > & _intnl_old
old values of internal parameters
RankTwoTensor _stress_trial
"Trial" value of stress that is set at the beginning of the return-map process.
virtual void setInelasticStrainIncrementAfterReturn(const RankTwoTensor &stress_trial, Real gaE, const yieldAndFlow &smoothed_q, const RankFourTensor &elasticity_tensor, const RankTwoTensor &returned_stress, RankTwoTensor &inelastic_strain_increment) const
Sets inelastic strain increment from the returned configuration This is called after the return-map p...
yieldAndFlow smoothAllQuantities(const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
Calculates all yield functions and derivatives, and then performs the smoothing scheme.
virtual void computeStressParams(const RankTwoTensor &stress, std::vector< Real > &stress_params) const =0
Computes stress_params, given stress.
MaterialProperty< Real > & _iter
Number of Newton-Raphson iterations used in the return-map.
MaterialProperty< RankTwoTensor > & _plastic_strain
plastic strain
std::vector< Real > _current_intnl
The current values of the internal params during the Newton-Raphson.
virtual void finalizeReturnProcess(const RankTwoTensor &rotation_increment)
Derived classes may use this to perform calculations after the return-map process has completed succe...
Real yieldF(const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
Computes the smoothed yield function.
bool precisionLoss(const std::vector< Real > &solution, const std::vector< Real > &stress_params, Real gaE) const
Check whether precision loss has occurred.
MaterialProperty< Real > & _linesearch_needed
Whether a line-search was needed in the latest Newton-Raphson process (1 if true, 0 otherwise) ...
std::vector< std::vector< Real > > _dvar_dtrial
d({stress_param[i], gaE})/d(trial_stress_param[j])
Real calculateRes2(const std::vector< Real > &rhs) const
Calculates the residual-squared for the Newton-Raphson + line-search.
virtual void setIntnlValuesV(const std::vector< Real > &trial_stress_params, const std::vector< Real > &current_stress_params, const std::vector< Real > &intnl_old, std::vector< Real > &intnl) const =0
Sets the internal parameters based on the trial values of stress_params, their current values...
std::vector< Real > _current_sp
The current values of the stress params during the Newton-Raphson.
bool _step_one
handles case of initial_stress that is inadmissible being supplied
virtual void errorHandler(const std::string &message) const
Performs any necessary cleaning-up, then throw MooseException(message)
virtual void preReturnMapV(const std::vector< Real > &trial_stress_params, const RankTwoTensor &stress_trial, const std::vector< Real > &intnl_old, const std::vector< Real > &yf, const RankFourTensor &Eijkl)
Derived classes may employ this function to record stuff or do other computations prior to the return...
std::vector< Real > _del_stress_params
_del_stress_params = trial_stress_params - ok_sp This is fixed at the beginning of the return-map pro...
const unsigned _max_nr_its
Maximum number of Newton-Raphson iterations allowed in the return-map process.
virtual void initializeReturnProcess()
Derived classes may use this to perform calculations before any return-map process is performed...
const MaterialProperty< RankTwoTensor > & _plastic_strain_old
Old value of plastic strain.
std::vector< Real > _rhs
0 = rhs[0] = S[0] - S[0]^trial + ga * E[0, i] * dg/dS[i] 0 = rhs[1] = S[1] - S[1]^trial + ga * E[1...
std::vector< Real > _ok_sp
The state (ok_sp, ok_intnl) is known to be admissible, so ok_sp are stress_params that are "OK"...
void dVardTrial(bool elastic_only, const std::vector< Real > &trial_stress_params, const std::vector< Real > &stress_params, Real gaE, const std::vector< Real > &intnl, const yieldAndFlow &smoothed_q, Real step_size, bool compute_full_tangent_operator, std::vector< std::vector< Real >> &dvar_dtrial) const
Calculates derivatives of the stress_params and gaE with repect to the trial values of the stress_par...
const unsigned _num_sp
Number of stress parameters.
Real MultiParameterPlasticityStressUpdate::yieldF ( const std::vector< Real > &  stress_params,
const std::vector< Real > &  intnl 
) const
protectedinherited

Computes the smoothed yield function.

Parameters
stress_paramsThe stress parameters (eg stress_params[0] = stress_zz and stress_params[1] = sqrt(stress_zx^2 + stress_zy^2))
intnlThe internal parameters (eg intnl[0] is shear, intnl[1] is tensile)
Returns
The smoothed yield function value

Definition at line 616 of file MultiParameterPlasticityStressUpdate.C.

Referenced by MultiParameterPlasticityStressUpdate::yieldAndFlow::operator<(), and MultiParameterPlasticityStressUpdate::updateState().

618 {
619  std::vector<Real> yfs(_num_yf);
620  yieldFunctionValuesV(stress_params, intnl, yfs);
621  return yieldF(yfs);
622 }
virtual void yieldFunctionValuesV(const std::vector< Real > &stress_params, const std::vector< Real > &intnl, std::vector< Real > &yf) const =0
Computes the values of the yield functions, given stress_params and intnl parameters.
const unsigned _num_yf
Number of yield functions.
Real yieldF(const std::vector< Real > &stress_params, const std::vector< Real > &intnl) const
Computes the smoothed yield function.
Real MultiParameterPlasticityStressUpdate::yieldF ( const std::vector< Real > &  yfs) const
protectedinherited

Computes the smoothed yield function.

Parameters
yfsThe values of the individual yield functions
Returns
The smoothed yield function value

Definition at line 625 of file MultiParameterPlasticityStressUpdate.C.

626 {
627  Real yf = yfs[0];
628  for (std::size_t i = 1; i < yfs.size(); ++i)
629  if (yf >= yfs[i] + _smoothing_tol)
630  // no smoothing is needed, and yf is the biggest yield function
631  continue;
632  else if (yfs[i] >= yf + _smoothing_tol)
633  // no smoothing is needed, and yfs[i] is the biggest yield function
634  yf = yfs[i];
635  else
636  yf = 0.5 * (yf + yfs[i] + _smoothing_tol) + ismoother(yf - yfs[i]);
637  return yf;
638 }
Real ismoother(Real f_diff) const
Smooths yield functions.
const Real _smoothing_tol
Smoothing tolerance: edges of the yield surface get smoothed by this amount.
void TensileStressUpdate::yieldFunctionValuesV ( const std::vector< Real > &  stress_params,
const std::vector< Real > &  intnl,
std::vector< Real > &  yf 
) const
overrideprotectedvirtual

Computes the values of the yield functions, given stress_params and intnl parameters.

Derived classes must override this, to provide the values of the yield functions in yf.

Parameters
stress_params[in]The stress parameters
intnl[in]The internal parameters
[out]yfThe yield function values

Implements MultiParameterPlasticityStressUpdate.

Definition at line 89 of file TensileStressUpdate.C.

92 {
93  const Real ts = tensile_strength(intnl[0]);
94  // The smoothing strategy means that the last yield function
95  // gives the smallest value when returning to a line/point where,
96  // without smoothing, the yield functions are equal.
97  // Therefore, i use the smallest eigenvalue in this yield function
98  yf[0] = stress_params[2] - ts; // use largest eigenvalue
99  yf[1] = stress_params[1] - ts;
100  yf[2] = stress_params[0] - ts; // use smallest eigenvalue
101 }
virtual Real tensile_strength(const Real internal_param) const
tensile strength as a function of residual value, rate, and internal_param

Member Data Documentation

const std::string MultiParameterPlasticityStressUpdate::_base_name
protectedinherited

String prepended to various MaterialProperties that are defined by this class.

Definition at line 144 of file MultiParameterPlasticityStressUpdate.h.

std::vector<std::vector<Real> > MultiParameterPlasticityStressUpdate::_Cij
protectedinherited
const std::vector<Real> MultiParameterPlasticityStressUpdate::_definitely_ok_sp
protectedinherited
RankTwoTensor TensileStressUpdate::_eigvecs
protected

Eigenvectors of the trial stress as a RankTwoTensor, in order to rotate the returned stress back to stress space.

Definition at line 40 of file TensileStressUpdate.h.

Referenced by consistentTangentOperatorV(), preReturnMapV(), and setStressAfterReturnV().

std::vector<std::vector<Real> > MultiParameterPlasticityStressUpdate::_Eij
protectedinherited
Real MultiParameterPlasticityStressUpdate::_En
protectedinherited
const Real MultiParameterPlasticityStressUpdate::_f_tol
protectedinherited
const Real MultiParameterPlasticityStressUpdate::_f_tol2
protectedinherited

Square of the yield-function tolerance.

Definition at line 159 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::updateState().

MaterialProperty<std::vector<Real> >& MultiParameterPlasticityStressUpdate::_intnl
protectedinherited
const MaterialProperty<std::vector<Real> >& MultiParameterPlasticityStressUpdate::_intnl_old
protectedinherited
MaterialProperty<Real>& MultiParameterPlasticityStressUpdate::_iter
protectedinherited

Number of Newton-Raphson iterations used in the return-map.

Definition at line 190 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::initQpStatefulProperties(), and MultiParameterPlasticityStressUpdate::updateState().

MaterialProperty<Real>& MultiParameterPlasticityStressUpdate::_linesearch_needed
protectedinherited

Whether a line-search was needed in the latest Newton-Raphson process (1 if true, 0 otherwise)

Definition at line 193 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::initQpStatefulProperties(), and MultiParameterPlasticityStressUpdate::updateState().

const unsigned MultiParameterPlasticityStressUpdate::_max_nr_its
protectedinherited

Maximum number of Newton-Raphson iterations allowed in the return-map process.

Definition at line 147 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::updateState().

const Real MultiParameterPlasticityStressUpdate::_min_step_size
protectedinherited

In order to help the Newton-Raphson procedure, the applied strain increment may be applied in sub-increments of size greater than this value.

Definition at line 166 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::updateState().

const unsigned MultiParameterPlasticityStressUpdate::_num_intnl
protectedinherited
const unsigned MultiParameterPlasticityStressUpdate::_num_sp
protectedinherited
const unsigned MultiParameterPlasticityStressUpdate::_num_yf
protectedinherited
const bool TensileStressUpdate::_perfect_guess
protected

Whether to provide an estimate of the returned stress, based on perfect plasticity.

Definition at line 37 of file TensileStressUpdate.h.

Referenced by initializeVarsV().

const bool MultiParameterPlasticityStressUpdate::_perform_finite_strain_rotations
protectedinherited
MaterialProperty<RankTwoTensor>& MultiParameterPlasticityStressUpdate::_plastic_strain
protectedinherited
const MaterialProperty<RankTwoTensor>& MultiParameterPlasticityStressUpdate::_plastic_strain_old
protectedinherited
const Real MultiParameterPlasticityStressUpdate::_smoothing_tol
protectedinherited
bool MultiParameterPlasticityStressUpdate::_step_one
protectedinherited

handles case of initial_stress that is inadmissible being supplied

Definition at line 169 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::updateState().

const TensorMechanicsHardeningModel& TensileStressUpdate::_strength
protected

Hardening model for tensile strength.

Definition at line 34 of file TensileStressUpdate.h.

Referenced by dtensile_strength(), and tensile_strength().

constexpr unsigned MultiParameterPlasticityStressUpdate::_tensor_dimensionality = 3
staticprotectedinherited
const bool MultiParameterPlasticityStressUpdate::_warn_about_precision_loss
protectedinherited

Output a warning message if precision loss is encountered during the return-map process.

Definition at line 172 of file MultiParameterPlasticityStressUpdate.h.

Referenced by MultiParameterPlasticityStressUpdate::updateState().

MaterialProperty<std::vector<Real> >& MultiParameterPlasticityStressUpdate::_yf
protectedinherited

The documentation for this class was generated from the following files: