Bridging the Gap from Multibody Simulations to Acoustic Analysis
Multibody simulation plays an essential role in the initial design phase of railway vehicles in which conceptual issues are investigated. It is as well the state-of-the-art method in order to study and optimize the running dynamics and comfort of railway vehicles in details. However, acoustic issues could not be ad ressed so far by multibody analysis. This is due to the fact that the validity of the used multibody models is restricted to the very low frequency range. In addition, multibody methodology is not prepared to evaluate acoustic measures in order to assess a railway vehicle under consideration.
Provided that these two short-comings are resolved, multibody analysis is capable of supplementing and enhancing the tools currently available for assessing railway acoustics such as TWINS, FEM or BEM. The high computational efficiency, the capability to perform time domain analysis, the reuse of model-components and scenarios originating from comfort evaluations are advantages that motivate the extension of the multibody methodology towards acoustic analysis.
Therefore, this paper presents model enhancements of the contact behavior of wheel and rail that are intended to be used in simulations in the frequency range up to 2.5 kHz and higher. Then the concept of an acoustic pre-processing tailored for multibody analysis is proposed based on the evaluation of the sound power on the surface of vibrating elastic bodies. Finally, an example is given in order to demonstrate the application of the proposed methodology.
KeywordsMultibody System Acoustic Analysis Impulsive Noise Flexible Body Railway Vehicle
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