The possibility of predicting brake pad wear is increasing in relevance for various reasons. A reliable wear prediction allows brake pads to be characterized more precisely in terms of emission behavior and service life. On the other hand, pads can be sized in a more purposeful way in early development stages. The dimensioning of brake pads plays a particularly important role in electric vehicles, as these are much heavier than conventional combustion vehicles due to their battery, but at the same time have the possibility of recuperation. Accordingly, the number of brake applications and the load spectrum of the brake system are also undergoing changes.
Pin-on-Disc Tribotesters are especially suitable for the investigation of brake pad wear, as they represent an economical possibility for the specific investigation of mechanisms in tribological contacts. In addition, the Automated Universal Tribotester (AUT) of the Institute for Dynamics and Vibration (IDS) offers the opportunity for high-precision quasi in-situ measurements of the wear height.
In order to achieve a systematic understanding of the wear behaviour of brake pads, stationary test cycles were performed at the AUT. Due to the great importance of the friction history with regard to the performance of automotive brake systems [see eg. OST13, OST19], it is essential, however, that the same load cycles as in real vehicles are metrologically investigated. For this purpose, the software of the AUT has been expanded, whereby real driving profile data from motor vehicles can be reproduced on the test bench.
From the information obtained by the stationary and instationary measurements, a wear model can be derived, which enables the estimation of the service life of brake pads in electrified vehicles during the early development process.
Jacek Kijanski, Research Engineer, TU Braunschweig; Mr. Johannes Otto, TU Braunschweig; Mr. Guido Lehne, TU Braunschweig; Dr.-Ing. Merten Tiedemann, Audi AG; Prof. Dr.-Ing. Georg-Peter Ostermeyer, TU Braunschweig