Optimal adaptation of acoustic black holes by evolutionary optimization algorithms

Abstract

The interest of engineers is focusing increasingly on a reduced sound radiation of constructions. In particular, structures with a large surface, such as cabin linings of airplanes as well as a roof or a bottom plate of cars, tend to be good acoustic radiators and lead to an annoyance of passengers. As countermeasures, often complex and time consuming design changes or expensive active measures are used. In many cases, a more elegant and cheaper option is to improve the acoustic properties by using passive measures. Acoustic black holes are an innovative passive method which combine two advantages: A material reduction by improving acoustic properties is performed.The main idea is to guide and to focus acoustically critical bending waves by a specific wall thickness diminution. Through targeted local damping placement in the middle of an acoustic black hole, a structure can be globally damped in a very efficient way. The efficiency depends on the position and size of the acoustic black holes [1]. Finding the optimal size and position on the structure is therefore an important challenge.This paper introduces a new strategy to find an optimal position of acoustic black holes to reduce the sound radiation of plane structures by using evolutionary optimization algorithms. Numerical calculations are exemplarily shown on a rectangular plate. (© 2016 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)