Abstract
In the present study, we consider a thin cylindrical shell and investigate vibroacoustic coupling between the shell vibration and the internal sound field when an external point force is applied to the shell wall. In order to understand this coupling phenomenon, characteristics of the shell vibration are considered from the viewpoint of the natural frequency and the vibration mode, which are induced by the Rayleigh-Ritz method. These theoretical results are demonstrated through the experimental modal analysis, using apparatus of which emulates the analytical model. The vibroacoustic coupling phenomenon is estimated by an excitation experiment, in which the same experimental apparatus is used and the acceleration on the shell wall and the sound pressure level inside the cylindrical shell are measured. These experimental results reveal that the proximity of the natural and resonance frequencies and the similarity between the vibration and acoustic modes are significant for the occurrence of vibroacoustic coupling, in particular, the lock-in phenomenon occurs even if both frequencies have a little difference.
