敷设声学覆盖层的圆柱壳体腔内噪声仿真分析

Simulation Analysis of Cylindrical Shell Cavity Noise with Acoustic Cover

针对飞机舱内噪声问题,将飞机机身等效为圆柱壳结构,采用实验研究和数值模拟相结合的方法研究圆柱壳内衬不同声学敷设材料的中低频(150Hz-700Hz)降噪特性。基于Virtual.lab Acoustic声学软件,建立有限元模型;并搭建实验装置,测得圆柱壳内部声学响应以验证模型在中低频段的准确性。数值模拟比较三聚氰胺泡沫和吸音棉的降噪效果,探究敷设材料厚度对降噪量的影响。结果表明:相同质量或相同厚度条件下,三聚氰胺泡沫的降噪效果均优于吸音棉的降噪效果。结果分析可得,材料敷设质量一定,厚度越小,单位厚度降噪效率越高;材料敷设面积一定,厚度越大,单位面积降噪效率越高。

In order to solve the problem of noise in the aircraft cabin, the airplane fuselage was dealt as an equivalent to the cylindrical shell structure, and based on that, the low frequency （ 150Hz -700Hz） noise reduction characteristics of different acoustic laying materials were studied by means of experimental study and numerical simulation. Based on Virtual. lab Acoustic software, the finite element model was established and the experimental device was built to measure the internal acoustic response of the cylindrical shell and verify the accuracy of the model in the middle and low frequency bands. Numerical simulation was used to compare the noise reduction effect of melamine foam and sound absorbing cotton, and the influence of laying material thickness on noise reduction was explored. The results show that the noise reduction effect of melamine foam is better than that of sound absorbing cotton under the same mass or the same thickness. The conclusion can be drawn as follow：for a given mass limit, the smaller thickness of the laying material, the higher efficiency of the unit thickness noise reduction; for a given area limit, the higher thickness of the laying material, the higher efficiency of noise reduction per unit area.