ExpJ2
Exponential Isotropic Hardening J2 Model
The kinematic hardening is not defined in this model.
Theory
The backbone function is defined as
\[
\sigma=\sigma_y\left(\left(1+a\right)e^{-b\varepsilon_p}-ae^{-2b\varepsilon_p}\right),
\]
where \(a\) and \(b\) are two constants that control the shape of the backbone. The initial stiffness \(\sigma'|_ {\varepsilon_p=0}=\sigma_y(a-1)b\).