User-defined soil material with temperature

Dear all,

I'm attempting to implement a constitutive model containing thermal variables (temperature rate) into Plaxis. The latest reference manual shows that Subroutine User_mod Sig0(18) and Sig0(19) are the temperature at the beginning of the current step and  the updated temperature, respectively. Do you know how to use Sig0 to define the temperature rate? I directly set delta_Temp_sub =(Sig0(18) - Sig0(19) )/number_steps, but It looks like the temperature is not updating during calculation.

Thanks