Damping term in PySimple1

[toy0410]

Greetings.

I am working on a project related to dynamic analysis of soil-pile systems using PySimple1 material to model the soil (spring). I have a few questions about the damping term ( $c) in PySimple1 material.
(1) Does $c include both hysteretic damping and radiation damping of the soil or just the radiation damping? DoＩneed to consider the damping of the pile in $c value of PySimple1?
(2) What is the best approach to determine the $c value, or what would be a reason range for me to pick the $c value?
(3) Is $c a damping ratio or a damping coefficient? In the document "PySimple1Gen OpenSees Command" by Dr. Scott Brandenberg, page 9/17, a c value of 1.5 is specified in the example. Is this giving a damping ratio of 150% or damping ratio of 1.5% or just a damping coefficient of 1.5?

Can PySimple1 generate the soil unloading curve and form the hysteritic loop during the dynamic analysis of soil-pile systems?

Thank you for the help

[Deneb]

Wow!

After reading this. I aware that some of my old analyses might be incorrect, due to the damping term in the model. Could anyone give me some "good" answers???