New method of damping structural vibrations based on the acoustic black hole effect

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The aim of the proposed project is to carry out theoretical and experimental investigations of the new efficient method of damping structural vibrations based on the specific features of flexural wave propagation and reflection in elastic wedge-like structures of power-law profile. The principle of operation of such structures is based on the recently discovered new class of 'wave trapping' phenomena that may take place in elastic wedges having cross sections described by a power law relationship between the wedge local thickness d and the distance from its edge x. In particular, for powers m = 2 and higher - in free wedges, and for powers m = 5/3 and higher - in immersed wedges, the incident flexural waves can be captured near the edges and therefore they never reflect back, i.e. the above structures materialise acoustic 'black holes' for flexural waves. In combination with narrow strips of thin absorbing layers attached to the edges, such wedge-like structures can provide very low reflections even in the case of real wedges of non-ideal power-law profile, thus implementing very efficient way of damping resonant flexural vibrations. In the proposed project, it is intended to further develop and investigate the proposed new method of damping structural vibrations based on the acoustic black hole effect. It is planned that several promising configurations of structures with acoustic black holes will be investigated in detail both theoretically and experimentally. The emphasis in the proposed project will be made on the so-called two-dimensional black holes that have not been investigated so far. The results of the project will lead to the development of new non-traditional and very efficient ways of damping structural vibrations that eventially could be used in different engineering applications.