2012 Volume 33 Issue 3 Pages 180-189
In the present paper, we describe vibroacoustic coupling between structural vibrations and the internal sound fields of thin structures. A cylindrical structure with thin plates at both ends is considered, and the coupling between the plate vibrations and the internal sound field is obtained when external harmonic forces are applied to both plates. This coupling is theoretically and experimentally investigated by considering the behavior of the plates and the acoustic characteristics of the internal sound field with variations in the harmonic forces. The acoustic characteristics are evaluated on the basis of the sound pressure level, which is maximized while changing the phase difference between the plate vibrations, when the phase difference and relative amplitude between the harmonic forces are varied. The behavior of the plate vibration is investigated by varying the phase difference with the cylinder length. Comparison of the characteristics of the systems reveals that vibroacoustic coupling is effective in increasing the acoustic energy and that the phase difference depends greatly on the acoustic mode, which contributes to the formation of the sound field. Moreover, the experiment of electricity generation verifies that vibroacoustic coupling is effective in the electricity generation system adopted in this investigation, if the coupling phenomena are promoted.
