尾轴承橡胶硬度对螺旋桨横向激振力引起艇体结构振动与声辐射特性的影响

摘要

从振源振动传递路径的声学设计的角度出发,以改变靠近螺旋桨后尾轴承橡胶夹层的橡胶硬度为具体措施,采用结构有限元法、结构有限元耦合流体边界元方法,以辐射声功率、湿表面均方法向速度作为衡量结构噪声辐射能力的主要衡量指标,系统地研究潜艇结构振动、辐射噪声谱峰频率和峰值的变化规律.计算结果表明:在低频段,随着后尾轴承橡胶硬度的增大,谱峰频率明显向高频移动,第一、二峰值都呈增大趋势;与传统的船用后尾轴承相比,采用带橡胶夹层的后尾轴承,在一定的频带范围内,能够有效地降低潜艇结构的振动和辐射噪声.因此,改变后尾轴承橡胶硬度,可以使谱峰频率向高频或低频移动,这样就能够使设备激振力的谱峰频率与结构振动及辐射噪声的谱峰频率错开,实现对辐射噪声的控制,达到减振降噪的目的.%From the angle of controlling transfer path of exciting force,adopting the method of modifying the rubber material hardness of stern bearing near the propeller,the structural finite element method and the structural finite element coupled fluid boundary element method are adopted for the numerical calculation.The acoustic radiation power and mean square normal velocities of the wet surface are adopted as the main indexes to estimate the acoustic radiation ability from the subroutine structures,and the characteristics of the vibration and acoustic radiation from the whole structure are studied systemically.From the result,in the lower frequency band,the peak value frequencies shift to higher frequency with the increasing of the rubber material hardness of stern bearing,and when the rubber material hardness of stern bearing increases to a certain value,the peak value frequencies tends to be stable,and basically unchanged.With the increasing of the rubber material hardness of stern bearing,the first peak value and the second peak value increase.When the rubber material hardness of the stern bearing increases to a certain value,the peak value frequencies tends to be stable,and basically unchanged.And compare with the traditional stern bearing,the stern bearing using the rubber for sandwich can decreases the vibration and noise effectively.And if the rubber material hardness of the stern bearing is smaller,in the whole frequency band,except the narrowband near the first peak value frequency,the level of vibration and noise decreases obviously.By modifying the rubber material hardness of the stern bearing,the peak value frequencies shift to higher frequency or lower frequency,and so that the spectral peak frequencies of the exciting force of the machines and the spectral peak frequencies of the vibration and noise are separated.And as a result,the noise and vibration are controlled.By decreasing the rubber material hardness of the stern bearing,in some frequency band,the vibration and noise of the submarine is reduced.