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降低飞机舱内的噪声首先要弄清引起舱内噪声的主要来源,以便采取合理有效的降噪措施。进入飞机舱内的噪声一般可分成两大类:空气声激励和机械激励下舱壁的声辐射。前者对舱内声场的贡献称为空气传声,后者称为结构传声。本文根据飞机壁板在机械激励和声场激励时,声辐射系数的差异,借助声强方法推导出两种不同激励下壁板辐射声功率的区分公式,并利用这些公式分别对均匀平板和加肋板进行了区分空气传声和结构传声的实验,计算区分结果和实验结果吻合较好。
Reduce the noise inside the aircraft cabin First of all, we must find out the main source of cabin noise in order to take reasonable and effective noise reduction measures. Noise entering the aircraft cabin can generally be divided into two broad categories: airborne excitation and mechanical excitation of bulkhead sound radiation. The former contribution to the cabin sound field is called airborne sound, the latter is called structural soundtrain. According to the difference of sound emission coefficient of aircraft siding between mechanical excitation and sound field excitation, this paper derives the distinction formula of radiated sound power under two different kinds of excitation by means of sound intensity method. By using these formulas, Experiments were made to distinguish the airborne sound and the structural soundtracks. The calculated results were in good agreement with the experimental ones.