Sound Radiation of Composite Panels Excited at Different Locations

• Main Authors: Jhang, Jyun- Jia, 張峻嘉
• Other Authors: Kam, Tai-Yan
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/61908997894239105857

碩士 === 國立交通大學 === 機械工程學系 === 100 === This thesis studies the sound radiation of strip-type flat plates excited at different locations. The purpose of exciting the plate at different locations is two-fold: Raise the sound pressure level (SPL) and improve the smoothness of the SPL curve. This study consists of three parts. In the first part, a Rayleigh-Ritz method is constructed to study the vibration of sound radiation plates which comprising a flat plate, a flexible surround, and a number of voice coils. In the mathematical model of the sound radiation plate, the vibration of the plate is formulated on the basis of the classical lamination theory. The flexible surround is treated as spring. The voice coils are modeled by simple beams. The accuracy of the method is verified by the finite element code ANSYS. In the second part, the vibration response of the plate is used in the first Rayleigh integral to construct the SPL curve of the plate. The experimental SPL curves as well as those obtained using ANSYS are used to validate the suitability of the present method for the analysis of sound radiation plates. Finally, the effects of excitation locations on the SPL curves of sound radiation plates are studied. The more appropriate locations of the voice coils are determined to minimize the magnitude of the sound pressure level drop in the mid-frequency range for the plates. The effects of the material constants of the sound radiation plates on the SPL curves are also studied theoretically. The results obtained in this thesis should be useful for the design of flat-panel speakers.