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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.

A systematic optimization of the Cohen class time-frequency transformation for detecting the parameters change is developed. The local moments approach to change detection is proposed and a general formula for the local moments is derived. The optimal kernel functions of the time-frequency transformation are determined based on the combined criteria of maximum sensitivity with respect to parameters change and minimum distortion of physical interpretation of the local moments. The sensitivity of the local moment with respect to a certain kind of inputs is analyzed and a most "convenient" and a "worst" input are identified. The results are presented in the form of the case studies for detecting parameters change in simple linear systems. / Graduation date: 1992

Kath. Univ., Diss. von Ivan Markovsky--Leuven. / Literaturverz. S. 197 - 202.

Thesis (Ph.D.)--Baylor University, 2008. / Includes bibliographical references (p. 70-74)

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Ashok Srinivasan, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Oct. 27, 2004). Includes bibliographical references.

David A. Castanon. / Bibliography: p. 28-29. / "Air Force Office of Scientific Research ... Grant AFOSR-80-0229."

by Milton B. Adams, Bernard C. Levy, Alan S. Willsky. / Bibliography: leaf [4]. / Caption title. "August 1983." / Supported by the National Science Foundation under Grant ECS-8012668

X.-C. Lou, J.R. Rohlicek, P.G. Coxson, G.C. Verghese, A.S. Willsky. / Bibliography: leaves 5-6. / "March 1985."

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