Design of wideband attenuation devices based on Sonic Crystals made of multi-phenomena scatterers

Vicente Romero-García , Sergio Castiñeira-Ibañez , Juan Vicente Sanchez-Perez , Lluis Miquel Garcia-Raffi

Sonic Crystals (SCs) are periodic structures of solid scatterers embedded in a fluid. Perhaps, the most celebrated property of SCs is the presence of ranges of frequencies, known as band gaps, where only evanescent modes are excited. As a consequence, in finite SCs the propagation of waves at these frequencies is attenuated. However the mere existence of these attenuation bands is not enough to design effective attenuation devices. In this work we report the theoretical and experimental design of multi-phenomena scatterers presenting resonances, absorption and scattering in the audible range. The design of the scatterers has been improved for its use outdoors. We use these scatterers to construct a periodic structure making use of the Bragg reflections, together with resonances and the absorption, in order to combine the three phenomena working independently in different ranges of frequencies. Thus the overall effect is a wideband of attenuated frequencies. The resultant device has been acoustically standardized obtaining the expected results, following the norms UNE-EN 1793-1:1998, 1793-2:1998 and 1793-3:1998. The structural efforts of these devices have been measured in an wind tunnel. The improvements with respect to the classical noise screens are discussed in the work.

Mots clés: Sonic Crystal Noise Barriers; Acoustic Resonators; Band Gaps

Domaines: Acoustique [physics.class-ph]

Vicente Romero-García, Sergio Castiñeira-Ibañez, Juan Vicente Sanchez-Perez, Lluis Miquel Garcia-Raffi. Design of wideband attenuation devices based on Sonic Crystals made of multi-phenomena scatterers. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810973⟩