摘要
Tubular acoustic metamaterials with negative densities composed of periodical membranes set up along pipes are studied with the fluid impedance theory.In addition to the conventional forbidden bands induced by the Bragg-scattering due to the periodic distributions of different acoustic impedances,the low-frequency forbidden band(LFB)with the low-frequency limit of zero Hertz is studied,in which the LFB is explained with acoustic impedance matching and the Bloch theory.Furthermore,the influences of the structural parameters of the tubular acoustic metamaterials on the transmission characteristics,such as the transmission coefficients,dispersion curves,widths of forbidden and pass bands,fluctuations in pass bands,etc.,are evaluated,which can be used in the optimization of the acoustic insulation ability of the metamaterials.
作者
范理
张淑仪
张辉
FAN Li;ZHANG Shu-Yi;ZHANG Hui(Lab of Modern Acoustics,Institute of Acoustics,Nanjing University,Nanjing 210093)
基金
Supported by the National Basic Research Program of China under Grant No.2012CB921504
the National Natural Science Foundation of China under Grant Nos.10904067 and 11174142
the Ph.D.Program of the Ministry of Education of China under Grant No.20090091120050
the PAPD of Jiangsu Higher Education Institutions.