Vehicle Dynamics Sortware

["Southerlin, Russell S" <russell.s.southerlin@lmco.com>]

> For you fellow geeks out there, I found some really interesting
> (free!)
>  vehicle dynamics simulation software.  Developed by University of 
> Michigan Transportation Research Institute (UMTRI).  They have a $$$ 
> non-free version, but this one is for students/cheapskates.
> 
> Check out
> 
> http://www.trucksim.com/carsimed.html
> 
> It has a fairly sophisticated 18-degree-of-freedom simulator which you
> 
> can plug all kinds of wild stuff into (tires, spring rates, damping, 
> roll rates, suspension geometry, camber, caster, toe, front/rear 
> weight bias, etc. etc.) and then run the thing with steering and brake
> 
> inputs.  Then you can animate/plot everything under the sun.  The 
> standard car model is independently suspended front and rear, and 
> looks sort of like an E36 4-door.  It's way cool watching it run over 
> a washboard surface with the distance between bumps getting shorter 
> and shorter. Then jack up the spring rates and watch your teeth 
> chatter.
> 
> So you can play with all these parameters and then evaluate lateral 
> g's, suspension travel, spring forces, etc.  and even run the car over
> 
> bumps and watch the suspension move.  You can even program in a 5-link
> 
> suspension and watch it react to bumps in 3-D.
> 
> Anybody have F/R roll center locations for an E36 M3?  How about 
> spring rates?  CG and pitch/roll/yaw moments?  I guess I could just 
> get out my string computer and measure them....would be a fun winter 
> project to create an M3 handling model and then look at changing 
> weight bias, various spring combos, sway bars, shocks, etc....I'll 
> just start with some crude estimates and see what happens.
> - -Al
>