Voce isotropic hardening

Overview

This object provides the Voce isotropic hardening. The isotropic hardening variable is defined as

$Q = -\sigma_0 -R \left( 1 - e^{-\delta \alpha} \right).$

The model requires a single history variable ( $\alpha$ ) and maps to a single hardening variable ( $Q$ ).

Warning

All of the NEML yield surfaces assume the opposite of the standard sign convention for isotropic and kinematic hardening. The hardening model is expected to return a negative value of the isotropic hardening stress and a negative value of the backstress.

Parameters

Parameter	Object type	Description	Default
`s0`	`neml::Interpolate`	Initial yield stress	No
`R`	`neml::Interpolate`	Saturated hardening increase	No
`d`	`neml::Interpolate`	Saturation rate constant	No

Class description

class VoceIsotropicHardeningRule : public neml::IsotropicHardeningRule 

Voce isotropic hardening.

Public Functions

VoceIsotropicHardeningRule(ParameterSet &params): Parameters: initial yield stress, total increase amount, saturation speed constant

virtual void q(const double *const alpha, double T, double *const qv) const: q = -s0 - R * (1 - exp(-d * alpha[0]))

virtual void dq_da(const double *const alpha, double T, double *const dqv) const: Derivative of map.

double s0(double T) const: Getter for initial yield stress.

double R(double T) const: Getter for R.

double d(double T) const: Getter for d.

Public Static Functions

static std::string type(): String type for the object system.

static std::unique_ptr<NEMLObject> initialize(ParameterSet &params): Initialize from a parameter set.

static ParameterSet parameters(): Default parameters.