Physical mechanisms of active control of sound transmission through rib stiffened double-panel structure

2016 ◽  
Vol 371 ◽  
pp. 2-18 ◽  
Author(s):  
Xiyue Ma ◽  
Kean Chen ◽  
Shaohu Ding ◽  
Haoxin Yu
Keyword(s):  
Active Control ◽  
Sound Transmission ◽  
Physical Mechanisms

scholarly journals Active Control of Sound Transmission through Orthogonally Rib Stiffened Double-Panel Structure: Mechanism Analysis

2019 ◽  
Vol 9 (16) ◽  
pp. 3286 ◽  
Author(s):  
Xiyue Ma ◽  
Kean Chen ◽  
Jian Xu
Keyword(s):  
Active Control ◽  
Cavity Mode ◽  
Control Mechanism ◽  
Sound Radiation ◽  
Sound Transmission ◽  
Base Plate ◽  
Mechanism Analysis ◽  
Coupling Effects ◽  
Physical Mechanisms ◽  
Cavity Modes

Physical mechanisms of active control of sound transmission through orthogonally two ribs stiffened double-panel structure are investigated. This is the continued work of the single rib stiffened case. For the orthogonally two ribs stiffened case, four different cluster mode groups can be coupled with each other, due to the interlaced coupling effects of the horizontal and vertical ribs. One cavity mode can couple with and transmit sound energy to any type of base plate mode of the radiating ribbed plate. Consequently, the main differences of the control mechanism, when compared with the single ribbed case, lie in two aspects. One is that a novel mechanism appears. That is, suppressing and rearranging the cavity modes simultaneously achieves the suppression of the base plate modes. The other is that rearrangement of the cavity modes to rearrange the base plate modes for achieving sound radiation cancellation almost does not appear. The reason is that all types of cavity mode can couple with any one of the base plate modes due to the coupling effects of the two ribs. There is only a need to rearrange several important cavity modes to achieve suppressing the base plate mode of the radiating ribbed plate.

Directional sound processing and interaural sound transmission in a small and a large grasshopper

1995 ◽  
Vol 198 (9) ◽  
pp. 1817-1827 ◽  
Author(s):  
A Michelsen ◽  
K Rohrseitz
Keyword(s):  
Outer Surface ◽  
Sound Pressure ◽  
Schistocerca Gregaria ◽  
Sound Transmission ◽  
Directional Hearing ◽  
Sound Processing ◽  
Low Frequencies ◽  
High Frequencies ◽  
Physical Mechanisms ◽  
Chorthippus Biguttulus

Physical mechanisms involved in directional hearing are investigated in two species of short-horned grasshoppers that differ in body length by a factor of 3­4. The directional cues (the effects of the direction of sound incidence on the amplitude and phase angle of the sounds at the ears) are more pronounced in the larger animal, but the scaling is not simple. At high frequencies (10­20 kHz), the sound pressures at the ears of the larger species (Schistocerca gregaria) differ sufficiently to provide a useful directionality. In contrast, at low frequencies (3­5 kHz), the ears must be acoustically coupled and work as pressure difference receivers. At 3­5 kHz, the interaural sound transmission is approximately 0.5 (that is, when a tympanum is driven by a sound pressure of unit amplitude at its outer surface, the tympanum of the opposite ear receives a sound pressure with an amplitude of 0.5 through the interaural pathway). The interaural transmission decreases with frequency, and above 10 kHz it is only 0.1­0.2. It still has a significant effect on the directionality, however, because the directional cues are large. In the smaller species (Chorthippus biguttulus), the interaural sound transmission is also around 0.5 at 5 kHz, but the directionality is poor. The reason for this is not the modest directional cues, but rather the fact that the transmitted sound is not sufficiently delayed for the ear to exploit the directional cues. Above 7 kHz, the transmission increases to approximately 0.8 and the transmission delay increases; this allows the ear to become more directional, despite the still modest directional cues.

Sound Transmission Through Simply Supported Finite Double-Panel Partitions With Enclosed Air Cavity

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
F. X. Xin ◽  
T. J. Lu ◽  
C. Q. Chen
Keyword(s):  
Sound Velocity ◽  
Velocity Potential ◽  
Transmission Loss ◽  
Elevation Angle ◽  
Sound Transmission ◽  
Double Fourier Series ◽  
Potential Method ◽  
Air Cavity ◽  
Simply Supported ◽  
Physical Mechanisms

The vibro-acoustic performance of a rectangular double-panel partition with enclosed air cavity and simply mounted on an infinite acoustic rigid baffle is investigated analytically. The sound velocity potential method rather than the commonly used cavity modal function method is employed, which possesses good expandability and has significant implications for further vibro-acoustic investigations. The simply supported boundary condition is accounted for by using the method of modal function and the double Fourier series solutions are obtained to characterize the vibro-acoustic behaviors of the structure. The results for sound transmission loss, panel vibration level, and sound pressure level are presented to explore the physical mechanisms of sound energy penetration across the finite double-panel partition. Specifically, focus is placed on the influence of several key system parameters on sound transmission including the thickness of air cavity, structural dimensions, and the elevation angle and azimuth angle of the incidence sound. Further extensions of the sound velocity potential method to typical framed double-panel structures are also proposed.

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