以二维双层弹性梁为例研究夹层声场的处理方法,从不同的物理视角,提出了夹层结构中夹层声场的横向声模态展开方法和声波导模态展开方法,并与夹层声场采用结构模态展开形式和声腔纯模态展开形式时的传声性能作对比,运用四种夹层处理方法计算了不同参数组合形式结构的传声损失。计算表明:夹层的横向声模态函数展开方法与结构模态展开方法在计算结构传声损失上是等价的;声波导模态函数展开方法在计算结构传声损失上与声腔模态展开方法是等价的;结构的传声损失曲线中的隔声低谷由结构共振、‘梁-空气-梁’共振以及驻波共振共同作用产生的结果;四种计算方法可以反映结构共振、‘梁-空气-梁’共振以及垂直与结构表面方向的驻波共振对结构传声损失的影响,除此而外,夹层的声模态展开形式和声波导模态展开还反映了平行于结构表面方向的驻波共振和其余的声模态对结构隔声性能的影响,因此在其对应的传声损失曲线中有更多的隔声低谷。
Abstract
Taking two-dimensional double-beam structural for example to study on the method of dealing with the sound filed of the sandwich structure, from different physical perspectives, The transverse acoustical modal expansion (TAME) method and acoustical waveguide modal expansion (AWME) method are presented to express the velocity potential of the air gap sound field of the sandwich structure and compare the sound transmission loss of the various parameter combined sandwich structure with the acoustical modal expansion (AME) method and structural modal expansion (SME) method. The calculation results show that the TAME method is equivalent to the SME method and the AWME method is equivalent to the AME method in the aspects of computing the sound transmission loss of the structure. The sound insulation dips are results of the combination of the structural resonances, ‘beam-air-beam’ resonance and standing-wave resonances. The four computing methods can reflect the influence of the structural resonances, ‘beam-air-beam’ resonance and standing-wave resonances with vertical to the structural surface on the structure of transmission loss. Besides, the AME method and AWME method can also reflect the influence of the standing-wave resonance with parallel to the structural surface and other acoustical modal frequencies on the structure of transmission loss, based on this reason, the sound transmission loss curve have much more dips than the former two methods.
关键词
夹层板结构 /
结构模态 /
声模态 /
声波导模态 /
共振频率
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脚注
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