直升机主减机匣结构振动噪声分析与优化

针对直升机主减速器机匣的振动噪声问题,对机匣进行基于频率响应和模态贡献量的结构动力学特性分析,给出机匣的振动特性,并确定对结构振动特性起主要影响的模态.利用间接边界元与有限元相结合的方法,应用基于结构面板声功率贡献量的分析方法,进行结构噪声功率分析和结构噪声功率面板贡献量分析,给出机匣的声学辐射特性,找出相应激励频率下对结构噪声功率贡献量最大的面板.以该面板为设计域进行结构拓扑优化,并根据优化结果合理布置加强筋,以提高结构刚度,达减振降噪的目的.结果表明:结构速度频率响应峰值下降了36%,减振效果良好,结构声功率级有了明显的降低,其中声功率级峰值下降了5dB,降噪效果良好,为直升机主减机匣提供了一种可行的减振降噪方法. 

Analysis and optimization of helicopter main gearbox housing structural vibration and noise

Structural dynamic performance analysis based on frequency response and modal contribution amount was presented about the problem of vibration and noise of helicopter main gearbox housing. The mode contributing most to the structural frequency response was found based on structural vibration performance. A method of analyzing panel acoustic power contribution amount of helicopter gearbox housing was presented based on combination of finite element method and indirect boundary element method. Acoustic radiation of the housing was simulated. The panel contributing most to the structural acoustic power under corresponding frequency was found. The panel mentioned above was the optimization area; stiffeners were reasonably arranged on the panel according to the optimization output. Result shows that,the maximum velocity frequency response has decreased 36%, vibration of the housing is attenuated, peak value of acoustic power level has decreased 5dB, and noise of the housing is reduced,which provides a feasible method to reduce noise and vibration for helicopter main gearbox housing.