Special issue: Recent advances in Acoustic Black Hole research

Abstract

Reduction of undesirable structural vibrations and of the associated structure-borne noise is a classical problem that remains important today. There are many ways of passive damping of structural vibrations. Unfortunately, most of them require addition of substantial amounts of damping materials, which is not always possible because of the mass and volume restrictions associated with structures' operational requirements. In this connection, development of new methods of vibration damping is always desirable, especially if they can avoid the mass or volume penalty. Among such new methods are those based on the Acoustic Black Hole effect (ABH), which is a topic of increasing interest in the vibroacoustic and noise control communities. In the majority of practical situations, this innovative technique for reduction of structural vibrations and of the associated noise is based on the propagation properties of flexural (bending) waves in thin structures of variable thickness. If a local thickness of a structure changes with wave propagation distance quickly enough, then such a structure may result in trapping the vibrations in the area of progressively decreasing thickness, in which a small patch of viscoelastic coating is sufficient to dissipate the localized energy very efficiently.The scientific literature on this subject has grown rapidly in recent years. In particular, a large number of research papers have been published in leading international journals

Research on Vibration Control of Base Structure with Composite Variable-thickness Wave Absorbing Damping Plate

“…Up to now, from the perspective of structural acoustic design, a lot of achievements have been made in reducing the vibration of the base structure and hull structure of the underwater vehicle equipment by setting variable-thickness plates locally. When the one-dimensional or two-dimensional plate structures [1][2][3][4] whose thickness varies according to the power function attenuation law with the exponent of power function of no less than 2 are used locally, the vibration characteristics of structures such as box structures 5,6 , raft structures 4 , and equipment bases 7 are studied by finite element analysis method, or the influence of structural parameters and structural forms of variable-thickness plates on the vibration reduction effect of target structures is analyzed by comparison between structural vibration tests and theoretical studies [8][9][10] . Both of them have concluded that variable-thickness plates can reduce the high-frequency vibration in the target structure.…”