降低加肋双层圆柱壳辐射噪声线谱的结构声学设计
Structural-Acoustic design to depress line spectrum of radiation noise from double cylindrical ring stiffened shell
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摘要: 为降低双层圆柱壳辐射噪声线谱,从控制内壳振动响应和衰减壳间振动传递率进行结构声学设计。采用机械阻抗理论分析了环肋圆柱壳模态响应控制机理;由环肋振动方程推导分析了环肋径向机械阻抗特性;基于阻抗失配、波形转换原理提出一种阻抗加强环肋,分析了振动波阻抑特性;利用阻尼减振技术,综合考虑肋板的刚度、阻尼特性,设计了金属橡胶层叠肋板;结合数值计算实例,分析了设计双层壳模型的声辐射性能。结果表明:设计的双层加肋圆柱壳结构能有效降低辐射噪声线谱,在分析频段内辐射声压线谱平均降低约6.6 dB。研究结果对研制低噪声水下航行器具有良好的工程价值和应用前景。Abstract: In order to reduce line spectrum of radiation noise from double cylindrical ring stiffened shell, structureacoustic design was done by the way of controlling inner shell's vibration response and attenuating wave transmissibility between two shells. Mechanical impedance theory was used to analyze mechanism of controlling modal response amplitude of ring-stiffened cylindrical shell The characteristic of radial modal mechanical impedance of the ring was analyzed Based on impedance mismatch and wave conversion a type of impedance enhancement rib was summed up and the vibration wave attenuation characteristic was analyzed. Considering the stiffness and damping of rib plate, metal rubber laminated rib-plate was proposed by applying damping vibration attenuation technology. Combined with specific calculation examples, the characteristics of vibration and sound radiation were analyzed. The results showed that the proposed double cylindrical ring stiffened shell could reduce radiation noise line spectrum effectively, the line spectrum of radiation pressure averagely decreased by 6.6 dB in analysis frequency band. It had a better engineering value and application prospect