为了研究夹层结构的声振耦合特性，提出了夹层声场的声波导模态展开方法，在此基础上发展了声波导模态展开方法的弱耦合形式，波导边界分别研究了绝对软边界和绝对硬边界两种形式，与结构模态展开方法和声腔模态展开方法及其弱耦合形式作对比，分析了声模态和声波导模态阶数对传声损失计算精度的影响，研究了不同夹层边界条件下夹层结构的声振耦合特性和夹层声场声压的分布情况。计算表明，需要的声波导模态阶数和声腔模态阶数由计算频率段的最高频率决定，最高频率越大，需要的声波导模态阶数和声腔模态阶数也越多；夹层结构的声振耦合特性是结构振动模态和声腔模态综合作用的结果，“梁-空气-梁”共振、驻波共振以及结构共振都会使得结构的隔声性能下降；夹层边界对结构的声振耦合特型有显著的影响；不同的夹层声场处理方法对于相同的物理现象得到的夹层声场分布不完全相同，从声场分布的特点可以反映所发生物理现象的机理。
Abstract
A kind of modal expansion forms based on acoustic waveguides modal is presented to investigate the vibro-acoustic coupling performance of the sandwich structures and its weak coupling forms is also developed. The boundary of the gap included two forms of pressure released boundary and rigid boundary. In comparison with structural modal expansion method and acoustic modal of the cavity, the influence of the orders of acoustic modal and acoustic waveguide on the calculation accuracy of the sound transmission loss is analyzed and the vibro-acoustic coupling performance and sound pressure distribution of gap were studied. It is shown that the needed number of the acoustic waveguide modal and acoustic modal of the cavity are determined by the highest frequency of interest; the bigger the highest frequency is, the more the number of the acoustic waveguide modal and acoustic modal of the cavity need. The comprehensive effect of structural vibration modal and acoustic modal act on the sandwich structures and affect its vibro-acoustic coupling responses. The ‘beam-air-beam” resonance, standing-wave resonance and structural resonance reduced the sound insulation performance of the structure. The boundary of the gap affects the vibro-acoustic of the structure obviously. The sound pressure distribution is different for the same physical phenomenon with three different methods and reveals the mechanism of the physical phenomena.
关键词
层板结构 /
结构模态 /
声模态 /
声波导模态 /
共振频率
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Key words
double panel structures /
structural modes /
acoustic modes /
acoustic waveguide modes /
resonance frequency
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参考文献
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