The popularity of vehicle anti-lock brake systems (ABS) leads to a demand for high-level optimization of tire friction properties, since it directly affects the ABS performance of vehicles. The design of pneumatic tires suited for various vehicles or their ABS regulation is required. The purpose of the present article is to propose a new treatment of tractive braking force, based on the analytical model of Fiala and Sakai. In the model, the braking force is expressed with the well-defined frictional parameters. The conventional treatment which assumes that the circumferential contact pressure profile of the tire with the road surface is approximated by a quadratic parabola function, represents the measured force with lower accuracy than the empirical models. A generalized skewed-parabola function is therefore applied to describe flexibly the variation of the actual contact pressure profile. In the generalized form of the Fiala-Sakai model certain values of slip rate are converted into corresponding values of the normalized adhesion length by the use of which one can calculate the shear stress in the adhesive zone and the sliding frictional force in the sliding zone of the tire contact patch. The summation of shear stress and sliding frictional force gives the total braking force generated in the entire contact patch. The modified model adequately approximates the measured my-S curves, and its least squares fitting yields the estimates of the adhesive friction coefficient, the sliding friction coefficient and the braking stiffness of the tread rubber compounds along with that of the front-inclined contact pressure profile during braking.
Analytical model of my-S curve using generalized skewed-parabola
Analytisches Reifenmodell
JSAE Review ; 24 , 1 ; 87-92
2003
6 Seiten, 6 Bilder, 6 Quellen
Article (Journal)
English
Analytical model of My-S curve using generalized skewed-parabola
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