Investigations into Vibration and Sound Transmission Characteristics of Cylindrical Shells

  • Ankim V. Swamy

    Student thesis: Doctoral ThesisDoctor of Philosophy

    Abstract

    This thesis describes an analytical and experimental study of the
    relationship between cylinder wall vibration and the resultant acoustic
    energy generated inside an enclosed stiffened cylinder representative
    of an aircraft fuselage.

    The work included measuring vibration and noise transmission
    properties of models simulating a fuselage. The results from these
    tests were used in the analytical predictions.

    Experimental facilities were developed for this work to measure
    parameters such as space average vibration and sound pressure levels,
    structural damping, transmission loss together with other relative
    parameters.

    Three cylindrical shell configurations were tested. Extensive
    experimental measurements were carried out to study various effects
    which are reported on noise and vibration characteristics. An
    emphirical approach was taken, to account for the internal loss factor.
    With this approach, a significant improvement was obtained in the
    comparison between analysis and experiment.

    relationship between the cylinder wall vibration and noise
    transmission characteristics were measured for both acoustical and
    mechanical forms of excitation. Below the ring frequency there was
    no direct comparison between the two measurements.

    Computer programs were. developed for the theoretical study of
    natural frequencies of cylinders and plates, and results are presented
    in the form of graphs and tables.
    Date of Award1972
    Original languageEnglish

    Keywords

    • vibration
    • sound transmission
    • cylindrical shells

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