水下蜂窝空腔覆盖层的隔声性能分析

Sound insulation performance of underwater honeycomb cavity covering

针对驻波管隔声量测试过程中,透射管末端反射波难以消除并对测试结果有一定影响的问题,利用LMS Virtual.lab有限元软件建立了驻波管隔声量测试的仿真模型。在模型中设置无反射边界条件,基于该模型分析了蜂窝空腔覆盖层的隔声性能,指出蜂窝空腔覆盖层的隔声特性是阻抗失配、波型转换、阻尼损耗等多种机理共同作用的结果,蜂窝结构的胞元壁厚、胞元夹角、黏弹性材料的杨氏模量等参数变化对隔声量的影响较为明显。消除了入射管端面和透射管端面的反射波,并通过与解析方法的计算结果对比验证了模型的正确性。

Because the reflected wave from the downstream tube can not be totally eliminated in the standingwave tube, which would affect the accurate measurement of sound transmission loss, the simulation model of measuring sound transmission loss in the standingwave tube is presented by using LMS Virtual.lab software. The nonreflected boundary conditions are defined in the present model. Then, the sound insulation performance of honeycomb cavity covering is analyzed and discussed based on the present model. It is summarized that the mechanism of sound insulation performance includes impedance mismatch, waveform transformation and damping loss. Moreover, the effects of the cell thickness, cell angle and viscoelastic Young’s modulus of the honeycomb structure on the sound insulation performance of honeycomb cavity covering are more obvious. The present model has been validated by comparing the numerical results of the analytical method, which can eliminate the reflected waves from the end surfaces of the upstream tube and the downstream tube.