Parametric Study of Sound Radiation Properties of Complex Vibration Patterns in Rectangular Plates using an Analytical Model
Parametric Study of Sound Radiation Properties of Complex Vibration Patterns in Rectangular Plates using an Analytical Model
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DOI：
10.3813/aaa.918866
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发表时间：
2015-07
影响因子：
--
通讯作者：
Oliver Unruh
中科院分区：
文献类型：
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作者：
Oliver Unruh
复杂的振动模式，其特征在于驻波和弯曲行波的叠加，例如在具有不均匀阻尼分布的结构中发生。复杂结构模态的存在引起了它们对声辐射特性的影响的问题。本文介绍了一种简支矩形板的分析模型。它允许快速计算具有不同属性的复杂振动模式，避免在有限元软件中进行耗时且有时不稳定的阻尼模态分析。利用该模型，可以生成具有不同水平和空间分布的行波以及不同对称性的振幅分布的振动模式，以揭示影响声辐射的重要因素。尽管事实上，分析模型产生理想化的振动模式，所提出的pathetaton显着提高了现象学的理解，在复杂的振动模式的声学效应。有限元模态分析的结果验证了所提出的模型的准确性，并在振动表面的振幅和相位分布方面进行了评估。利用模态辐射效率、远场声强空间分布和声场指向性对两种方法的结果进行了比较。使用有关结构振动模式的重要声学指标的分析模型得出了一些额外的结论。结果表明，偶数阶振型对行波的辐射能力和声压场特性非常敏感。
Complex vibration modes, which can be characterised by the superposition of standing and travelling bending waves, occur for instance in structures with inhomogeneous damping distribution. The existence of complex structural modes raises the question of their influence on sound radiation properties. In this paper an analytical model of a simply supported rectangular plate is introduced. It allows a quick calculation of complex vibration patterns with different properties, avoiding time consuming and sometimes unstable damped modal analysis in finite-element-software. Using this model it is possible to generate vibration patterns with varying level and spatial distribution of travelling waves as well as different symmetry of amplitude distributions, in order to reveal the important influence factors on sound radiation. Despite the fact that the analytical model generates idealised vibration patterns, the presented consideraton significantly improves phenomenological understanding of acoustic effects in complex vibration modes. The accuracy of the presented model is validated by results of finite element modal analysis and is evaluated in terms of resulting amplitude and phase distributions of the vibrating surface. The results of both suggested approaches are compared using modal radiation efficiencies, spatial distributions of far field acoustic intensity and sound field directivity. Some additional conclusions are made using the analytical model concerning important acoustic metrics of structural vibration patterns. It is shown, that vibration shapes of even order are very sensitive to the presence of travelling waves regarding their radiation capability and character of sound pressure field.