Mr. Sven Brandt, TU Braunschweig, GERMANY

Mr. Malte Sandgaard, TU Braunschweig, GERMANY

Dr.-Ing. Sebastian Gramstat, Audi AG, GERMANY

Mr. Frank Stebner, Volkswagen AG, GERMANY

Mr. Conrad Weigmann, Volkswagen AG, GERMANY

Prof. Dr.-Ing. Arno Kwade, Institute of Particle Technology, GERMANY

Prof. Dr.-Ing. Georg-Peter Ostermeyer, TU Braunschweig, GERMANY

Prof. Dr.-Ing. Carsten Schilde, Institute of Particle Technology, GERMANY

The increasing degree of electrification as well as the optimization of particle based exhaust emissions, which is already being driven forward due to legislation, will direct the focus of fine dust considerations in automotive technology to non-exhaust emissions. In contrast to exhaust emissions, there are currently only a few vehicle-related limit values or uniform standards in measurement technology and the measurement procedure. The area of non-exhaust emissions includes tire abrasion, the turbulence of organic and inorganic road particles, and brake wear. Since, in addition to the material component, the particle size also has a significant influence on the health hazard of the material, particulate emissions from brakes are often directly related to health effects.

In comparison to previous measurements, which have mostly been carried out in enclosed and clinical environments, the dynamics of the fine dust emitted from the brake will be investigated using a fully automated tribometer and used as a possibility to validate a DEM simulation. Besides the pure measurement of the emitted particle size distributions during the brake application, conclusions on the agglomeration behaviour of the emission particles in the environment shall be drawn. The aim is to predict the environmental impact and the potential danger of the particles to humans due to the particle size released into the environment. The pin-disc contact between brake pad and brake disc serves as the emission source. A coupled CFD-DEM simulation environment was set up to simulate particle dynamics. Based on a rotating brake disc model, the flow-relevant components of the test bench environment were implemented into the simulation setup. The area around the actual brake contact as well as the environment at the tribometer should be considered. For the metrological validation of the simulation, a swarm of calibrated low-cost sensors as well as a scattered light based particle size measuring device will be set up around the tribometer.

Prof. Dr.-Ing. Georg-Peter Ostermeyer, TU Braunschweig, GERMANY

Mr. Andreas Krumm, TU Braunschweig, GERMANY

Dr.-Ing. Frank Schiefer, TU Braunschweig, GERMANY

Mr. Sebastian Montua, Faiveley Transport Bochum GmbH, GERMANY

As in many other industries, weight reduction also plays an important role in the product development of train manufacturers and suppliers. Due to the ongoing weight reduction of the bogie and the components, they are becoming increasingly sensitive to NVH phenomena. A particularly critical component here is the brake, as the non-linear friction contact between the brake pad and the disc makes it predestined for self-excited vibration phenomena and thus for NVH phenomena. In this paper, vibration phenomena known from field tests will be investigated with respect to their systemic influence. Three different models of bogie brakes are considered to perform a complex eigenvalue analysis (CEA), where the level of detail of the model and the boundary conditions are different. The first model is a very detailed model of the brake with highly simplified boundary conditions. The second model is an extension of the first model where an additional wheel axle has been added. By including the axle, the brake disc gets additional degrees of freedom, where additional vibrations can be considered. The third model includes an entire wheel set with brake units. This model has been simplified to investigate phenomenologically vibrations of the entire wheelset and to consider systemic influences. With these three models an evaluation of the influence of the boundary conditions on the NVH behaviour should be carried out. For all modal analyses, the real part of the eigenvalue is used as an essential evaluation criterion and is applied to evaluate the impact of the boundary conditions on the observed vibration phenomena or the stability of the eigenfrequencies. Thereby a sensitivity analysis of the individual boundary conditions with respect to the eigenfrequencies is also a target.

Prof. Dr.-Ing. Georg-Peter Ostermeyer, TU Braunschweig, GERMANY

Mr. Chengyuan Fang, TU Braunschweig, GERMANY

Mr. Felix Rickhoff, TU Braunschweig, GERMANY

The frictional behavior of a tribological contact is the result of complex interactions between two bodies.

In the case of tribological high-load contacts, such as those found in brakes, wear and the associated wear particles play a particularly important role. In the last two decades, a number of papers have been written on this subject, which explain the highly complex dynamics of the friction coefficient, among other things, with the self-organization structures of the wear material in the tribocontact.

Here, particle concentrations, so-called patches, form, which act like additional contact areas in the boundary layer. Since they change dynamically, the friction performance shows similar dynamic structures.

But the ejection of wear particles is also the current focus of research. The emissions also exhibit dynamic signatures.

This work wants to present the further developed measurement technique as well as first approaches to describe the wear particle transport in the boundary layer by experiment and simulation.