I am trying to find the theoretical "under-the-hood" information on the FE formulation solidworks simulation is using so I can be more precise in a report I am writing. In particular I am looking for the rigorous fatigue calculations going on in that module so I can feel comfortable using it.

I was able to locate a "Simulation Theory Manual" pdf in my installation directory, however it appears woefully out of date (I am running 2016). For one, it only addresses basic static stress, vibration, buckling and heat transfer. Also, it only defines 5 elements (TRUSS3D, BEAM3D, RBAR, SPRING, SHELL3T, SHELL3)!!  Where are all the 3D element definitions??

The report I am preparing is typically done with a NASTRAN type software where all the background mathematics are well understood and publicized. Anyone know of a reference for simulation? I found an old cosmos theoretical manual with the info I require, am I safe to assume SWsimulation is running the same code?