Enhancement of Wave Energy Dissipation in Two-Dimensional Acoustic Black Hole by Simultaneous Optimization of Profile and Damping Layer

Acoustic black hole (ABH) effect in thin-walled structures provides drastic wave focalization. In a practical ABH structure with a tapering thickness profile, the concentrated wave energy can be efficiently dissipated by introducing a damping layer to the local high energy density area. In this paper, simultaneous optimization of the geometric parameters of the ABH profile and the topology of the damping layer covering the ABH area is investigated based on the former study of wave focalization. To optimize the ABH structure for achieving maximum energy dissipation, parametric modelling is implemented, and the dissipated energy is computed by the commercial finite element software Abaqus. The optimal geometric parameters of the ABH thickness profile are obtained by the method of moving asymptotes (MMA). The topological optimization problem of the damping layer is solved by using optimality criteria (OC). These two algorithms are nested alternatively in the main optimization procedure. The influence of mesh size and direction of wave incidence on the optimization is discussed. Numerical results show that the proposed approach is efficient in finding the optimal design for the ABH structure to achieve maximum wave energy dissipation. In addition, the influence of coupling between the host ABH plate and the layer on the optimization is investigated. Superior performance of energy dissipation is achieved by the proposed method comparing to the results before the optimization. (C) 2020 Elsevier Ltd. All rights reserved.