Investigations on Tribological Memory Effects in Friction Materials

Friction materials for automotive brakes are known to exhibit a time-dependent tribological behavior. When examining these dynamic effects special demands are made on the measurement device: The influences of the brake system should be minimized and parameters like velocity, contact pressure and temperature should be controlled closely and independently. Furthermore, special test procedures need to be designed. This can ideally be achieved using a scaled tribometer like the High-Load-Tribometer at the Institute of Dynamics and Vibrations in Braunschweig.

Former investigations [1] have shown that a kind of memory effect can occur for a low-met brake pad rubbing on a cast iron disk. A variation of the initial disk temperatures has revealed that a temporary increase of the coefficient of friction can occur at slightly elevated temperatures. This effect is memorized by the material as a certain procedure needs to be performed in order to achieve a regeneration. The scope of the current work is to extend this examination with respect to different materials and also include different load cases. It will be studied if effects, like the formerly described, are limited to certain materials and what conditions enable their occurrence.

Date Published: 2014-09-28
Author(s): Lars Wilkening, Hans-Guenther Paul, Georg Peter Ostermeyer

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