Vibro-acoustic analysis of uncased drive systems

In spite of the manufacturers' extensive efforts to reduce noise emission by empirical optimisation processes, the emission values of some types of off-road machines, especially those with intensive operating process noise or uncased drive systems like crawler tracks, exceed the desired limit values. Furthermore the necessary optimisation loops increase both development time and costs. The effective identification of further reduction potential requires sophisticated acoustic system understanding which does not solely include the noise emission but also the sound excitation and transmission. Especially when considering components and structures which can not be encapsulated, this holistic approach becomes particularly important. Ideally the acoustic system understanding is not only based on extensive measurements, but rather generated by the development of virtual prototypes which can already be applied during the design process. The paper introduces a hybrid approach for obtaining acoustic system understanding developed by the "Research Group for Off-Road Machines" at the Ruhr-University of Bochum in cooperation with the "IBAF-Engineering GmbH". To illustrate that approach which is characterised by a close interaction of measurements and simulation, the article exemplarily describes the acoustic optimisation of crawler tracks. The results displayed in this paper are taken from a research project carried out at the Ruhr-University in Bochum.