Acoustic characteristics of a sound field inside a cylindrical structure with excited end plates: Influence of excitation position on vibro-acoustic coupling

Abstract

Vibro-acoustic coupling between plate vibrations and the sound field inside a cylindrical structure is investigated. Each end plate of the cylindrical structure is excited by a point force. When the excitation position, which directly affects the vibration characteristics of the plates, is examined by shifting the point of application radially along the plate, the sound field is estimated based on the contribution defined as the ratio of acoustic energy stored in each acoustic mode to the total acoustic energy in the entire sound field. Coupling is intensified by the coincidence of a circumferential order with respect to the modes of plate vibration and of the sound field. Therefore, if the vibration modes at the two end plates have different orders due to the influence of the excitation position, then the sound field is composed of a number of acoustic modes. In particular, excitation at a position near the greatest flexural displacement causes the vibration energy to increase, and the contribution of the corresponding acoustic mode also increases. However, approaching the nodal circle of plate vibration, the excitation position develops coupling solely with the other plate vibration, because the occurrence of the vibration mode is restrained.

Electricity Generation Characteristics of Energy-Harvesting System with Piezoelectric Element Using Mechanical-Acoustic Coupling

“…We used the above-mentioned analytical model [6,7] of a cylindrical structure with plates at both ends to investigate the effect of the excitation frequency, at which the coupling system becomes nonperiodic owing to the application of excitation forces of different frequencies to the respective end plates, on the mechanical-acoustic coupling [8]. Then the effect of the excitation position with respect to the nodal lines on the appearance of vibration modes on the plates was investigated [9]. Finally, because a phase difference between both plate vibrations affects strongly mechanicalacoustic coupling, this coupling was considered in the cases, in which one end plate and both end plates were excited by a harmonic point force, respectively [10,11].…”

Energy Harvesting with Piezoelectric Element Using Vibroacoustic Coupling Phenomenon

“…In addition, the excitation frequency at which the coupling system becomes nonperiodic owing to the application of excitation forces of different frequencies to the respective end plates was investigated [12]. Finally, the effect of the excitation position with respect to the nodal lines on the appearance of vibration modes on the plates was investigated [13]. On the other hand, to suppress the above vibration and acoustic energy, which was amplified by vibroacoustic coupling, an analytical model that included the installation of passive devices on the vibration system was proposed as the electromechanical-acoustic system.…”

Vibroacoustic coupling of cylindrical enclosure with excited end plates

“…In addition, the excitation frequency at which the coupling system becomes aperiodic owing to the application of excitation forces of different frequencies to the respective end plates has been investigated [8]. Finally, the effect of the excitation position with respect to nodal lines on the appearance of vibration modes on the plates has also been investigated [9].…”