Overlapping of acoustic bandgaps using fractal geometries

¹ Departamento de Física Aplicada, Universidad Politécnica de Valencia - Camino de Vera s/n, 46022 Valencia, Spain, EU
² Instituto de Ciencia de Materiales, CSIC - Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain, EU
³ Centro de Tecnologías Físicas: A.M.A., Universidad Politécnica de Valencia - Camino de Vera s/n, 46022 Valencia, Spain, EU
⁴ Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia - Camino de Vera s/n, 46022 Valencia, Spain, EU

^a jusanc@fis.upv.es

Received: 21 June 2010
Accepted: 11 October 2010

Abstract

The transmission of acoustic waves in a fractal distribution of rigid scatterers embedded in air is reported in this work. The Sierpinsky fractal is used to produce a compact small device containing several periodicities, therefore the fractal distribution contains several finite sonic crystals. The attenuation band produced by the fractal distribution results from the sum of the Bragg peaks of each periodicity. On the other hand, bandgaps of sonic crystal depend on the well-known filling fraction, thus the radii of the scatterers in the fractal distribution has been optimized using genetic algorithm in order to overlap the bandgaps of each periodicity obtaining a wide and full attenuation band.