ZWT Model Implementation LS DYNA

Dear All,

I mean to implement the ZWT model (A non-linear viscoelastic model) broadly described in this paper.

[URL] https://www.mdpi.com/1996-1944/11/9/1565/htm [/URL]

I followed all the steps, however, my model is not showing any viscoelasticity. Can anybody help please?
Thanks in advance.
Dakshitha