Power law isotropic hardening

Overview

This object provides power law isotropic hardening. The isotropic hardening variable is defined as

$Q = -\sigma_0 - A \alpha^n.$

The model requires a single history variable ( $\alpha$ ), which is the equivalent plastic strain, 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
`A`	`neml::Interpolate`	Prefactor	No
`n`	`neml::Interpolate`	Work hardening exponent	No

Class description

class PowerLawIsotropicHardeningRule : public neml::IsotropicHardeningRule 

Power law hardening.

Public Functions

PowerLawIsotropicHardeningRule(ParameterSet &params): Parameters: initial yield stress, prefactor, exponent.

virtual void q(const double *const alpha, double T, double *const qv) const: q = -s0 - A * alpha[0]**n

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

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.