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采用虚拟预测方法研究某发动机壳体的振动特性及噪声辐射特性.采用有限元法分析发动机壳体在振动加速度激励下的动态响应,得到壳体表面的振动速度频谱图,并与试验所得壳体上典型点的振动速度频谱图进行对比,仿真结果与试验结果吻合较好.将计算得到的壳体所有外表面节点的振动速度作为边界元模型的输入载荷,导入到声学仿真分析软件中,计算由壳体表面振动而辐射出的噪声,并用声强试验进行验证,对比了理论计算数据与试验数据,两者的噪声分布云图及噪声源中心点处的声强频谱图,并分析了误差产生的原因,结果表明,采用有限元法与边界元法联合求解的方法能够有效地预测出壳体辐射噪声.
The vibration characteristics and the noise radiation characteristics of an engine case were studied by using the virtual prediction method.The dynamic response of the engine case under the vibration acceleration excitation was analyzed by the finite element method.The vibration velocity spectrum of the case surface was obtained and compared with the experimental case The results of the simulation are in good agreement with the experimental results.The vibration velocity of all the outer surface nodes of the shell is taken as the input load of the boundary element model and imported into the acoustic simulation software to calculate The noise radiated by the vibration of the shell surface was verified by the sound intensity test. The theoretical calculation data and the experimental data were compared. The noise distribution of the two images and the sound intensity spectrum at the center of the noise source were compared. The results show that the combination of finite element method and boundary element method can effectively predict the shell radiation noise.