ASA 125th Meeting Ottawa 1993 May

3aSA10. Vibrations and acoustic radiation of a simply supported cylindrical shell under circumferentially moving loads: Modeling and experiments.

Raymond Panneton

Frederic Laville

Alain Berry

G.A.U.S., Univ. of Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada

The vibrational and acoustical behaviors of a simply supported cylindrical shell, immersed in a light fluid and excited with circumferentially moving radial loads are considered in the frequency domain. The equation of motion is developed using an energy method. To solve the problem, the shell displacements and boundary pressures are expanded in a series of in vacuo shell modes. The circumferentially moving loads induce a displacement with spatial and temporal dependences of the form e[sup jN(cursive phi)] and e[sup -jN(Omega)t], where N is an integer and (Omega) is the rotational speed of the loads. For this type of dependence, the equation of motion shows critical speeds for which the modal amplitudes are maximum. Also, a modal analysis is conducted to describe the general behavior of the shell, in the frequency domain, in terms of quadratic velocity, radiated sound power, and radiation efficiency under moving loads. This analysis shows that high levels of quadratic velocity and radiated sound power occur for the critical speeds of rotation. In order to validate this modeling, numerical results are compared with previous published works and laboratory experiments. This paper is the continuation of the paper presented at 124th ASA Meeting [J. Acoust. Soc. Am. 92, 2387 (A) (1992)].