Noise path identification for vibro-acoustically coupled structures

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2004

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Şerafettinoğlu, A. Hakan

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Structures of machinery with practical importance, such as home appliances or transportation vehicles, can be considered as acoustically coupled spaces surrounded by elastic enclosures. When the structures of machinery are excited mechanically by means of prime movers incorporated into these structures through some elastic connections, generation of noise becomes an inevitable by-product. For noise control engineering purposes, a thorough understanding of emission, transmission and radiation of sound from structure is required prior to a possible and practical modeling of noise transfer mechanisms. Finally, development of a model for complete noise generation and transfer mechanisms is needed which is essential for the abatement of annoying sound generation. In this study, an experimental and analytical (finite element) methodology for the modal analysis of acoustical cavities is developed, and successfully applied to a case study. The acoustical transmission problem of the structure is investigated via vector intensity analysis. Results of this investigation are used for a noise path qualification, whereas the transfer functions between sources of noise and some relevant receiving points are obtained by use of vibro-acoustic reciprocity principle. The concept of transfer path analysis is investigated by using the multi input, multi output linear system theory for vibro-acoustic modeling of machinery structures. Finally, resolution and ranking of noise sources and transfer paths are accomplished via spectral correlation methodologies developed. The methodology can be extended to any system with linear, time invariant parameters, where principles of superposition and reciprocity are applicable.

Subject Keywords

Noise control.

URI

http://etd.lib.metu.edu.tr/upload/3/12604829/index.pdf
https://hdl.handle.net/11511/14106

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

A. H. Şerafettinoğlu, “Noise path identification for vibro-acoustically coupled structures,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.