Experimental Investigations on Sound-Structure Investigations by Using Modal Testing

聲場與結構互制之實驗研究：低頻分析

白明憲(M. R. Bai) ； 林怡岩(Y. Y. Lin)

《中華民國振動與噪音工程學會論文集》 1994 (1994/06) Pp. 214-221

https://doi.org/10.30028/CSSVANNUAL.199406.0214

摘要

針對一聲場與結構之耦合系統，爲了預測由內部聲場壓力所引致的結構振動，本研究發展出三種實驗方法，即UST，RST和CST。其中UST忽略了聲壓負載效應，將聲場與結構當成非耦合的子系統來處理，即視聲場壓力爲作用於結構上之外力，再依據由模態測試所推導出的結構模態模式，來預測由聲壓外力所引致的結構振動大小。而RST和CST視聲場與結構爲一耦合系統，將聲壓負載效應列入考慮，應用模態測試找出耦合系統的動態特性，以建立聲場壓力與結構振動之間的關係，做爲預測結構振動的基礎，二者最大不同在於RST只適用於共振頻率；而CST則可應用於任何頻域。爲了驗証所提出的方法，我們在鋼製圓柱殼內裝置一喇叭激振，以探討圓柱殼的表面振動，各方法之預測能力將在最後做一比較，且實驗結果所得的物理意義也將做一歸納。

並列摘要

Three experimental methods entitled the Uncoupled System Technique (UST), the Resonant System Technique (UST), and the Coupled System Technique (CST) are presented for prediction of structural vibrations induced by internal acoustic excitations. UST neglects acoustic loading and treats the problem as uncoupled subsystems. In RST and CST, the acoustic field and the structure are considered as a coupled system. The experimental results of a steel cylindrical shell show that CST provides the most accurate predictions.