This document explains the physical assumptions, internal structure and usage of the models of the Advanced LIGO suspensions written in Mathematica by Mark Barton ("the Mathematica model" as opposed to "the Matlab model" of Calum Torrie, Ken Strain et al.).
2025-01-27: The previous OneDrive link stopped working (file could be opened online but not in the desktop app), so a new one was created and added in the Abstract.