Contact models - meaning of "modifiable"

Hey everyone,

when I was implementíng the contact model for my numerical simulation with PFC, I went through the documentation of the rolling resistance linear model and noticed the collumn “modifiable”. I’ve originially thought that you can only assign values for modifiable parameters like the normal and the shear stiffness, but a colleague told me that it is also possible to assign a value to the E-modulus, a non-modifiable parameter.
Can somebody explain me what the actual meaning of modifiable is?

Thank you in advance

Best regards

Dear Nick,
sorry for the slow response. Below you can see the link to the Rolling Resistance Linear Model
Rolling Resistance Linear Model — PFC 7.0 documentation)

Your colleague is indeed correct that the E-modulus (and also the kratio) can be set even though they are marked as Not-Modifiable. This can also be seen in the following example.
Rolling Resistance Linear Contact Model: Repose Angle — PFC 7.0 documentation (

However, they can only be set using the deformability method and not the {contact property} command. That is the reason why they are marked as Not-Modifiable.

All further Not-Modifiable properties can not be set at all and are read only.
Sorry for the confusing classification.