One of the key selling criteria of brake linings is their related cost per life time. Individual wear rates must match a required service interval which in most cases is part of the warranty a vehicle is sold with.
OEMs, brake manufacturers as well as friction material suppliers are therefore conducting in-depth investigations on the wear behaviour of brake systems and their friction pair. These consider various parameters influencing pad and rotor life expectancy as part of the pre selection process before running final fleet trials for confirmation. Thus, selecting the right test procedures and parameters for the determination of wear rates is key in enabling a confident life time prediction.
As of today, a multitude of wear test procedures are used in the automotive industry, each of them related to the specific experience of the respective OEM or BM. The main parameters in all of them, more or less, relate to similar parameters, i.e. energy dissipation, temperature and sliding speed of the friction couple.
In this paper, the main differences in the most commonly used procedures are described and analysed regarding their capability to achieve a life time prediction expected under real driving conditions. A set of comparative tests are performed to confirm and quantify the impact of the influencing parameters on wear. The outcome of this investigation shows that wear rate and related life expectancy predictions are not only dependent on energy dissipation and individual braking conditions, such as temperature and sliding speed at the friction surface but also to a great extent on the sequence of the individual brake applications.
As an outcome of the investigation, a methodology is presented which allows a better integration of the relevant influencing parameters resulting in a higher confidence levels in life time prediction.