At limit tire treatment for chassis design
At limit tire treatment for chassis design
(OP)
Most equations for chassis design involve the tires cornering stiffness which is zero at its peak lateral force for a given condition. Just looking in Miliken this zeros out a lot of values if you were designing a neutral car that in theory all tires reached the limit at the same time or if you were analysing a car simply at the lateral force limits at each tire in the conditions being analyzed. This seems unrealistic, partly because it is, but I was curious if there was another type of analysis of design approach for when the tire is not in the neutral region...?
RE: At limit tire treatment for chassis design
As for limit behaviour, more knowledgeable members than myself should point you in right direction... Substituting this or that in linear range equations would IMHO be a big no-no, because there are simplifications (not often visible at a first glance) involved in linear range equations.
RE: At limit tire treatment for chassis design
Milliken's method of moments is a great way of looking at steady state limit handling, and it based on equations.
For limit handling I don't use equations much, mainly simulations. If equations were used all I'd really do is check that the front saturates first, ie that we have limit understeer, but more typically I look at brake in turn, double lane change, throttle on/off in turn, and some other tests. I don't run a simple skidpan test typically, oddly enough.
Cheers
Greg Locock
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RE: At limit tire treatment for chassis design
RE: At limit tire treatment for chassis design
RE: At limit tire treatment for chassis design
However most people seriously interested in vehicle dynamics have written simulators of some form, whether a bicycle model or a 4 wheeled bike, or a full blown multi body dynamics simulator. Since the weakpoint is almost invariably the tire model or data the complexity of the vehicle model on top of it makes surprisingly little difference to the utility of the model.
Milliken's moment method is actually a full vehicle simulation, it's just there are no pretty pictures to keep the managers happy, just one big scary graph.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?