The development process of a bogie brake is a complex one, as the brake, as a safety-relevant component, has to fulfil a number of functions and characteristics. The correct prediction of vibration and, in particular, NVH phenomena, therefore plays a central role in the development process. This will become even more important in the future due to the increasing demand for lightweight construction. In order to test brakes in the development process, there are not only tests on test benches and on the track, but also the possibility of predicting vibrations by simulation. The challenge in the development process is to find a suitable test bench for the brake and the simulation in order to correctly represent the loads and dynamic behaviour. This article shows vibration phenomena that cannot be measured on the test bench, but which cause significant NVH phenomena in the train. Acceleration measurement data is analysed and compared in the time and frequency domain of dynamometer and field tests with respect to the vibration behaviour of the brake in different braking scenarios. FEM simulations are used to better understand the difference between bench and field testing. The stability behaviour of the railway brake is investigated in the frequency domain using a complex eigenvalue analysis (CEA). Two different boundary conditions of the brake are implemented and compared. The first boundary condition represents the test bench and the second boundary condition represents a complete wheelset with wheel-rail contact. The results show that essential vibration phenomena cannot be detected on the test bench. This is where simulation can provide a clear insight. The simulations show that the dynamic behaviour of the wheelset has an influence on the results of the brake. A coupling of wheelset bending modes and unstable brake modes cannot be detected by simulating only one the brake under test bench conditions. This study describes a critical NVH phenomenon of railway brakes and wheelsets and investigates the mechanism. Such phenomena are becoming increasingly important due to the trend towards lightweight construction. In addition, special attention must be paid during the development process to ensure that appropriate test and simulation conditions are used for the dynamic design of the railway brakes in order to detect and eliminate critical phenomena in the vehicle.
Mr. Andreas Krumm, Research Engineer, TU Braunschweig, Institut for Particeltechnologie; Prof. Dr.-Ing. Georg-Peter Ostermeyer, Professor, TU Braunschweig, Mechanical Engineering; Dr.-Ing. Frank Schiefer, Senior Research Engineer, TU Braunschweig, Institut for Particeltechnologie