薄膜型声学超材料隔声特性研究

Sound Insulation Properties of Membrane-type Acoustic Metamaterials

为对一种薄膜型声学超材料的设计提供理论指导,对其隔声性能、影响因素和应用展开研究。构建薄膜型声学超材料的声学仿真模型,开展其隔声性能的单一影响因素和多因素正交优化设计研究,探讨方形声学超材料在汽车前围板上的组合应用。研究表明,随着薄膜厚度或预应力的增加,薄膜型声学超材料单胞的传声损失曲线整体向高频区域移动,传声损失峰值及其所对应的频率均明显增大,有效隔声频率范围变宽;质量块厚度的改变可以在某些频率范围内改变传声损失峰值及其所对应的频率;对薄膜型声学超材料单胞隔声性能影响最大的设计参数是薄膜厚度,其次是薄膜预应力;优化设计后的声学超材料单胞的平均传声损失达到30.2 dB,峰值传声损失81.0 dB比优化前的53.8 dB高50.5%;在材料结构与性能参数相同情况下,方形单胞具有比圆形单胞更好的低频隔声性能;组合后应用于前围板的方形声学超材料可以明显提高传统钢前围板的低频隔声性能。

In order to provide theoretical guidance for design of a membrane-type acoustic metamaterial(MAM),its sound insulation performance,influencing factors and applications were studied.The acoustic simulation model of the MAM was established,the single influencing factor and the multi-factor orthogonal optimization design of the sound insulation performance were studied,and the combined application of square acoustic metamaterial in the car dash panel was discussed.Research results show that with the increase of membrane thickness or membrane prestress,the curve of sound transmission loss(STL)for the MAM moves towards the high frequency region as a whole,the peak values of transmission loss and their corresponding frequencies increase obviously,and the effective sound insulation frequency range becomes wider.The thickness change of the mass block can alter the peak values of the STL and their corresponding frequencies in some frequency range.The design parameter that has the greatest influence on the sound insulation performance of the MAM is the membrane thickness,followed by the membrane prestress.The average STL of the optimized MAM reaches 30.2 dB,and the peak value of the optimized STL is 81 dB which is higher than that of the original MAM 53.8 dB by 50.5%.Under the condition of the same material structure and property parameters,the square MAM has a better lowfrequency sound insulation performance than the round MAM.The square MAM combined application in the car dash panel can obviously improve the sound insulation performance of the traditional steel car dash panel in the low frequencies.