Creep models

Overview

Creep models in NEML relate stress and strain to a creep strain rate. This means they do not maintain a set of internal history variables. Currently, they are only used in conduction with a standard NEML material model through the creep+plasticity metamodel.

NEML creep models fulfill the interface

So the creep strain rate can depend on the stress, the total strain, time, and temperature.

Implementations

• J2 creep
  • Overview
  • Scalar creep models
    • Scalar creep models
      • Overview
      • Implementations
        • Power law creep
          • Overview
          • Parameters
          • Class description
            • PowerLawCreep
              • PowerLawCreep::PowerLawCreep()
              • PowerLawCreep::g()
              • PowerLawCreep::dg_ds()
              • PowerLawCreep::dg_de()
              • PowerLawCreep::A()
              • PowerLawCreep::n()
              • PowerLawCreep::type()
              • PowerLawCreep::initialize()
              • PowerLawCreep::parameters()
        • Power law creep
          • Overview
          • Parameters
          • Class description
            • NormalizedPowerLawCreep
              • NormalizedPowerLawCreep::NormalizedPowerLawCreep()
              • NormalizedPowerLawCreep::g()
              • NormalizedPowerLawCreep::dg_ds()
              • NormalizedPowerLawCreep::dg_de()
              • NormalizedPowerLawCreep::type()
              • NormalizedPowerLawCreep::initialize()
              • NormalizedPowerLawCreep::parameters()
        • Regime switching Kocks-Mecking creep
          • Overview
          • Parameters
          • Class description
            • RegionKMCreep
              • RegionKMCreep::RegionKMCreep()
              • RegionKMCreep::g()
              • RegionKMCreep::dg_ds()
              • RegionKMCreep::dg_de()
              • RegionKMCreep::type()
              • RegionKMCreep::initialize()
              • RegionKMCreep::parameters()
        • Norton-Bailey creep
          • Overview
          • Parameters
          • Class description
            • NortonBaileyCreep
              • NortonBaileyCreep::NortonBaileyCreep()
              • NortonBaileyCreep::g()
              • NortonBaileyCreep::dg_ds()
              • NortonBaileyCreep::dg_de()
              • NortonBaileyCreep::A()
              • NortonBaileyCreep::m()
              • NortonBaileyCreep::n()
              • NortonBaileyCreep::type()
              • NortonBaileyCreep::initialize()
              • NortonBaileyCreep::parameters()
        • Mukherjee creep
          • Overview
          • Parameters
          • Class description
            • MukherjeeCreep
              • MukherjeeCreep::MukherjeeCreep()
              • MukherjeeCreep::g()
              • MukherjeeCreep::dg_ds()
              • MukherjeeCreep::dg_de()
              • MukherjeeCreep::A()
              • MukherjeeCreep::n()
              • MukherjeeCreep::D0()
              • MukherjeeCreep::Q()
              • MukherjeeCreep::b()
              • MukherjeeCreep::k()
              • MukherjeeCreep::R()
              • MukherjeeCreep::type()
              • MukherjeeCreep::initialize()
              • MukherjeeCreep::parameters()
        • Generic creep law
          • Overview
          • Parameters
          • Class Description
            • GenericCreep
              • GenericCreep::GenericCreep()
              • GenericCreep::g()
              • GenericCreep::dg_ds()
              • GenericCreep::dg_de()
              • GenericCreep::type()
              • GenericCreep::initialize()
              • GenericCreep::parameters()
        • Blackburn minimum creep rate model
          • Overview
          • Parameters
          • Class description
            • BlackburnMinimumCreep
              • BlackburnMinimumCreep::BlackburnMinimumCreep()
              • BlackburnMinimumCreep::g()
              • BlackburnMinimumCreep::dg_ds()
              • BlackburnMinimumCreep::dg_de()
              • BlackburnMinimumCreep::dg_dT()
              • BlackburnMinimumCreep::type()
              • BlackburnMinimumCreep::initialize()
              • BlackburnMinimumCreep::parameters()
        • Swindeman minimum creep rate model
          • Overview
          • Parameters
          • Class description
            • SwindemanMinimumCreep
              • SwindemanMinimumCreep::SwindemanMinimumCreep()
              • SwindemanMinimumCreep::g()
              • SwindemanMinimumCreep::dg_ds()
              • SwindemanMinimumCreep::dg_de()
              • SwindemanMinimumCreep::dg_dT()
              • SwindemanMinimumCreep::type()
              • SwindemanMinimumCreep::initialize()
              • SwindemanMinimumCreep::parameters()
        • Minimum creep law for 2.25Cr-1Mo steel
          • Overview
          • Parameters
          • Class description
            • MinCreep225Cr1MoCreep
              • MinCreep225Cr1MoCreep::MinCreep225Cr1MoCreep()
              • MinCreep225Cr1MoCreep::g()
              • MinCreep225Cr1MoCreep::dg_ds()
              • MinCreep225Cr1MoCreep::dg_de()
              • MinCreep225Cr1MoCreep::type()
              • MinCreep225Cr1MoCreep::initialize()
              • MinCreep225Cr1MoCreep::parameters()
      • Class description
        • ScalarCreepRule
  • Class description
    • J2CreepModel
      • J2CreepModel::J2CreepModel()
      • J2CreepModel::f()
      • J2CreepModel::df_ds()
      • J2CreepModel::df_de()
      • J2CreepModel::df_dt()
      • J2CreepModel::df_dT()
      • J2CreepModel::type()
      • J2CreepModel::initialize()
      • J2CreepModel::parameters()

Class description

class CreepModel : public neml::NEMLObject, public neml::Solvable

Interface to creep models.

Subclassed by neml::J2CreepModel

Public Functions

CreepModel(ParameterSet &params)

Parameters are a solver tolerance, the maximum allowable iterations, and a verbosity flag

void update(const double *const s_np1, double *const e_np1, const double *const e_n, double T_np1, double T_n, double t_np1, double t_n, double *const A_np1)

Use the creep rate function to update the creep strain.

virtual void f(const double *const s, const double *const e, double t, double T, double *const f) const = 0

The creep rate as a function of stress, strain, time, and temperature.

virtual void df_ds(const double *const s, const double *const e, double t, double T, double *const df) const = 0

The derivative of the creep rate wrt stress.

virtual void df_de(const double *const s, const double *const e, double t, double T, double *const df) const = 0

The derivative of the creep rate wrt strain.

virtual void df_dt(const double *const s, const double *const e, double t, double T, double *const df) const

The derivative of the creep rate wrt time, defaults to zero.

virtual void df_dT(const double *const s, const double *const e, double t, double T, double *const df) const

The derivative of the creep rate wrt temperature, defaults to zero.

void make_trial_state(const double *const s_np1, const double *const e_n, double T_np1, double T_n, double t_np1, double t_n, CreepModelTrialState &ts) const

Setup a trial state for the solver.

virtual size_t nparams() const

Number of solver parameters.

virtual void init_x(double *const x, TrialState *ts)

Setup the initial guess for the solver.

virtual void RJ(const double *const x, TrialState *ts, double *const R, double *const J)

The nonlinear residual and jacobian to solve.