Implementing a custom yield function using available models NEML2.

[sarkas6]

Hello,

I wanted to ask if it is possible to implement the following custom yield functions by using available models in NEML2 or if a custom model implementation is needed.

$\phi (\tilde{\rho},\sigma_{ij},T)=\sigma_{eq}(\tilde{\rho},\sigma_{ij}) - \sigma_y$

where
$\sigma_{eq}(\tilde{\rho},\sigma_{ij}) = \left ( 3c(\tilde{\rho})J_2 + f(\tilde{\rho})I^2_1 \right )^{0.5}$, $c(\tilde{\rho})$, $f(\tilde{\rho})$ are some calibration functions dependent on an internal variable $\tilde{\rho}$.

Thank you.

[hugary1995]

Yes, take a look at the GTNYieldFunction for an example. We use this family of yield functions quite often for poromechanics.