IsoJ2I1¶

Overview¶

This object implements the yield function

$f\left(\bm{\sigma}, \mathbf{q}, T\right) = J_2\left(\bm{\sigma}\right) + \sqrt{\frac{2}{3}}Q + \operatorname{sign}\left(I_1\left(\bm{\sigma}\right)\right) h \left(I_1\left(\bm{\sigma}\right)\right)^l J_2\left(\mathbf{Y}\right) = \sqrt{\frac{3}{2} \operatorname{dev}\left(\mathbf{Y}\right): \operatorname{dev}\left(\mathbf{Y}\right)} I_1\left(\mathbf{Y}\right) = \operatorname{tr}\left(\mathbf{Y}\right).$

It assumes a “stress-like” history vector of

$\mathbf{q}=\left[\begin{array}{c}Q\end{array}\right]$

where $Q$ is the isotropic hardening stress.

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
`h`	`neml::Interpolate`	Power law prefactor	No
`l`	`neml::Interpolate`	Power law exponent	No

Class description¶

class IsoJ2I1 : public neml::IsoFunction<IsoKinJ2I1>¶

Isotropic only version of J2I1 surface.

Public Functions

inline IsoJ2I1(ParameterSet &params)¶

Public Static Functions

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

static std::unique_ptr<NEMLObject> initialize(ParameterSet &params)¶: Initialize from parameters.

static ParameterSet parameters()¶: Default parameters.