音響ダイオードのトポロジー最適化について

抄録

We propose a topology optimisation for designing acoustic diodes which realise uni-directional transmission of sound wave. Several types of acoustic diodes based on different physical mechanisms have been proposed so far. In this study, we focus on a phononic-crystal-based acoustic diode. We can design such an acoustic diode by maximising so-called diodicity i.e. the difference between transmittance of a wave from one direction and that from the opposite direction. We derive the topological derivative of the diodicity and discuss a fast boundary element method to evaluate the topological derivative numerically. With the topological derivative, optimal design of acoustic diode is explored by a topology optimisation with level-sets of B-spline surfaces. We present numerical examples showing that the proposed topology optimisation can find a periodic structure with high diodicity.