Regular Article

Large band gaps in radial phononic crystal structure with round mass block

¹ School of Mechanical Engineering and State Key Laboratory for Strength and Vibranon of Mechanical Structures, Xi’an Jiaotong University, Xi’an 710049, P.R. China
² School of Mechanical Engineering, Xi’an Jiaotaong University, Xi’an 710049, P.R. China

^a e-mail: gaonansha@hotmail.com

Received: 1 December 2015
Revised: 24 April 2016
Accepted: 2 May 2016
Published online: 24 June 2016

Abstract

Using the finite element method, we theoretically study the vibration properties of radial phononic crystal (RPC) structure with round mass block. The band structures, transmission spectra, and displacement fields of eigenmode are given to estimate the starting and cut-off frequency of band gaps. Compared to the contrast structure, numerical calculation results show that RPC structure with round mass block can yield several band gaps below 150 kHz. The physical mechanism of band gaps are attributed to the coupling between the longitudinal vibration in round mass block and vibrations in outer frame or coating layer. By changing geometrical dimensions r of round mass block, we can shift the location and width of band gaps. Significantly, as the increase of geometric parameter ratio a₁/a₂, band width shifts and the more new band gaps appear; the more bands become flat at this moment because of the stronger multiple vibration coupling effect plays a more prominent role in the opening of band gaps. These vibration properties of RPC structure with round mass block can potentially be applied to optimize band gaps, generate filters, and design acoustic devices.