Looking for material to control unloading strain

[structurestudent]

I am looking for a material that enables us to control the ε0 as 0.3 times maximum ε as shown in the picture below.

Referred from;https://opensees.berkeley.edu/OpenSees/ ... index.html

There are some materials in which we can control the unloading slope, but is there any material we could control ε0 equal to 0.3 times maximum ε?

I would like to ask for any advice.
Thank you