Bh. Houston et al., THE STRUCTURAL ACOUSTICS AND ACTIVE CONTROL OF INTERIOR NOISE IN A RIBBED CYLINDRICAL-SHELL, The Journal of the Acoustical Society of America, 99(6), 1996, pp. 3497-3512
Numerical studies are carried out regarding the structural acoustics o
f a ribbed aluminum cylindrical shell structure intended to represent
the essential structural features of a small aircraft fuselage. Calcul
ations are made to determine both the wall normal displacements and th
e interior acoustic pressures for the case in which the shell wall is
forced dynamically at a point. The structural responses are further de
composed into their frequency-wave-number components. Through a series
of comparisons between those responses for an infinite shell, the rib
bed vacuum-filled shell, and the ribbed air-filled shell, the relevant
structural acoustic mechanisms are interpreted. The frequencies at wh
ich interior acoustic ''resonances'' are observed are connected to spe
cific mechanisms, including cavity responses driven by structural mode
s, cavity modes forcing the structure, and mixed structure/air-cavity
modes. Numerically based active control experiments are carried out us
ing end actuation, and the relative performance of this control ''syst
em'' is compared when operating on the various mode types.