Analysis of different techniques to improve sound transmission loss in cylindrical shells

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• 作者：Pouria Oliazadeh ; Anooshiravan Farshidianfar ; ^{farshid@um.ac.ir}
• 关键词：Double &ndash ; walled shell ; Triple &ndash ; walled shell ; Coincidence frequency ; Ring frequency ; Transmission loss
• 刊名：Journal of Sound and Vibration
• 出版年：2017
• 出版时间：17 February 2017
• 年：2017
• 卷：389
• 期：Complete
• 页码：276-291
• 全文大小：2769 K
• 卷排序：389

文摘

In this study, sound transmission through double- and triple-walled shells is investigated. The structure-acoustic equations based on Donnell's shell theory are presented and transmission losses calculated by this approach are compared with the transmission losses obtained according to Love's theory. An experimental set-up is also constructed to compare natural frequencies obtained from Donnell and Love's theories with experimental results in the high frequency region. Both comparisons show that Donnell's theory predicts the sound transmission characteristics and vibrational behavior better than Love's theory in the high frequency region. The transmission losses of the double- and triple-walled construction are then presented for various radii and thicknesses. Then the effects of air gap size as an important design parameter are studied. Sound transmission characteristics through a circular cylindrical shell are also computed along with consideration of the effects of material damping. Modest absorption is shown to greatly reduce the sound transmission at ring frequency and coincidence frequency. Also the effects of five common gases that are used for filling the gap are investigated.