Active control of elastic metamaterials consisting of symmetric double Helmholtz resonator cavities. (April 2019)

• Record Type: Journal Article
• Authors: Ning, Li; Wang, Yi-Ze; Wang, Yue-Sheng
• Is Part Of: International journal of mechanical sciences. Volume 153/154(2019)
• Page Start: 287
• Page End: 298
• Publication Date: 2019-04
• Subjects: Active control -- Elastic metamaterials -- Helmholtz resonators -- Effective bulk modulus -- Acoustic cloaking; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2019.02.007
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: A new class of active elastic metamaterials is presented. A cloaking design consisting of double Helmholtz cavities with active control action is proposed. Some interesting phenomena (e.g. negative effective bulk modulus and cloaking) are shown. Abstract: Wave invisibility has quite special meaning on marine vehicles under water, which encourages people to search effective methods for a long history. Initiated by this point, we propose a new class of active elastic metamaterials and a cloaking design consisting of double Helmholtz cavities. By changing external voltage with different piezoelectric diaphragm stiffness, this structure shows a controllable effective bulk modulus in which a negative value appears over a wide frequency range. This configuration with double active cavities provides better tunable abilities to achieve the effective bulk modulus than that with a single cavity. In order to design a multilayered cloak and a non-blind cloak, the coupling of the adjacent cavity cells is considered and the control strategy for the periodic cavities with active Helmholtz resonators is developed. The parameters of the multilayered acoustic cloak can be obtained by the coordinate transformation method and the corresponding effective medium theory. This action can be implemented by the active control on each unit cell to drive the distribution of effective bulk modulus. These characteristics with a tunable effective bulk modulus at a very wide frequency range are significant to control elastic wave propagation. Graphical abstract: Image, graphical abstract With the active control action, a non-blind cloak is compared. The pressure field of the non-blind cloak is well distributed because of the active control. And the pressure field of the non-blind cloak is nearly undisturbed.