关键词: 负模量/
声学超材料/
低频宽带
English Abstract
Low-frequency wide-band mechanism of a new type acoustic metamaterial with negative modulus
Zhang Yong-Yan1,2,Wu Jiu-Hui1,
Zhong Hong-Min2
1.School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China;
2.School of Mechanical Engineering, Sichuan University of Science and Engineering, Zigong 643000, China
Received Date:12 December 2016
Accepted Date:13 February 2017
Published Online:05 May 2017
Abstract:In this paper, a new type of acoustic metamaterial with negative modulus is proposed, and the formation and broadening mechanism of the low frequency bandgap are revealed. The expression of the normalized effective modulus of the structure is derived theoretically. Since the zero value of the effective modulus is closely related to the system parameters, the appropriate parameters can be adjusted to reduce the zero point, and the lower bound of the bandgap is reduced, thus the low-frequency bandgap is realized. The theoretical results show that the elastic modulus of the system is negative and the region of the negative modulus is widened in a certain frequency range, therefore, the widening of the bandgap can be realized through the enlargement of the negative modulus region. This new mechanism for achieving low-frequency bandgap overcomes the shortcomings both in the traditional local resonance with too large additional mass, and in the inertial amplification structures with narrow bandgaps. At the same time, the transmission of this periodic structure obtained by the finite element method is highly consistent with that by the theoretical analysis, with a low-frequency band of 40-180 Hz, from which the new mechanism presented here is verified. This new idea of achieving low-frequency bandgap is of great theoretical significance for controlling low-frequency sound waves.
Keywords: negative modulus/
acoustic metamaterial/
low-frequency broadband
