局域共振型平板结构的低频振动与声辐射特性分析

Analysis of Low Frequency Vibration and Acoustic Radiation Characteristics of Locally Resonant Plate Structures

抑制低频振动与辐射噪声对提高水下航行器的声隐身性能具有重要意义。首先建立含局域共振元胞的平板结构横向振动模型,采用模态叠加法和谐波平衡法导出耦合振动方程的解析解,其次给出5 Hz~300 Hz范围内平板表面平均振速级与辐射声功率级解析表达式,研究元胞中吸振器参数对平板声振特性的影响,最终对目标频段平板结构的振动控制效果进行优化设计。研究表明:研究的频率范围内,局域共振型平板结构在吸振器固有频率附近会产生能够抑制其低频振动与噪声的频带;随吸振器阻尼的增大,减振频带拓宽且减振降噪性能减弱;多振子元胞具有多个减振频带,频带的叠加使得其低频减振降噪性能优于单振子元胞;经粒子群算法优化后在目标频段单振子、双振子、四振子元胞的减振降噪效率分别可达到26.3%、29.8%、29.1%。研究结果可为水下航行器低频振动以及噪声的控制提供参考。

Controlling the low frequency vibration and radiation noise is important for improving acoustic stealth performance of underwater vessels.The transverse vibration model of the plate structure with local resonant cells was established.Employing the modal superposition method and the harmonic balance method,the analytical solution of the coupled vibration equation was derived.The average vibration velocity level and the radiation sound power level of the plate structure surface in the range of 5 Hz-300 Hz were given,and the influence of the parameters of the vibration absorber in the cells on the acoustic vibration characteristics of the plate was investigated.The vibration control effects of the plate structure in the target frequency band were optimized.The results show that within the frequency range,the local resonant plate structure can generate a frequency band that can suppress its low-frequency vibration and noise in the frequency range adjacent to the natural frequency of the vibration absorber.With the increase of vibration absorber damping,the bandwidth is widened and the vibration and noise reduction performance is weakened.The multi-vibrator cell has multiple frequency bands,and the superposition of frequency bands makes the low frequency vibration and noise reduction performance better than that of a single-vibrator cell.After optimization by the particle swarm algorithm,the vibration and noise reduction efficiencies of single,double,and four-vibrator cells in the target frequency band can reach 26.3%,29.8%,and 29.1%respectively.The research results provide some advances for controlling the low frequency vibration and noise of underwater vessels.