Multiobjective design optimization of a tunable acoustic switch using multiresonant asymmetric scatterers

Abstract This study introduces a multiobjective (MO) optimization framework for designing a tunable acoustic switch based on multiresonant asymmetric scatterers arranged in a periodic sonic crystal (SC) lattice. The multiresonant SC exploits the interplay between the Bragg bandgap (Bragg-BG) and the local resonance BG (LR-BG), induced by the Helmholtz resonators (HRs), to enable switchable acoustic transmission in the low to mid-frequency range (500–2500 Hz). By rotating the scatterers by 90 $$^{\circ }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mo>∘</mml:mo> </mml:mmultiscripts> </mml:math> , the system dynamically controls the frequency ranges for acoustic insulation and transmission. The proposed optimization framework employs the $$\epsilon $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ϵ</mml:mi> </mml:math> -variable MO genetic algorithm ( $$\epsilon $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ϵ</mml:mi> </mml:math> v-MOGA), targeting two key performance metrics: the contrast ratio ( CR ) and the absolute difference (Diff) in transmission between orthogonal orientations of the scatterers. Geometric parameters of the HR-inspired SC neck and the internal separation wall angle are optimized under 3D-printability constraints. Numerical simulations, validated by experimental measurements on a 3D-printed prototype, demonstrate enhanced tunable acoustic wave transmission with complementary BGs in the perpendicular orientations and improve the switching performance compared to the initial design. This approach provides a simple, robust, and cost-effective solution for tunable acoustic filtering, overcoming limitations of existing passive and complex active metamaterial switches. Our findings offer valuable insights for designing adaptive acoustic devices, advancing applications in noise control and acoustic wave manipulation.