Noise Certification of a Sonic Crystal Acoustic Screen designed using a Triangular Lattice according to the Standards EN 1793(-1;-2;-3): 1997
Invited paper
Universitat Politécnica de València
Wednesday 3 june, 2015, 10:20 - 10:40
0.9 Athens (118)
Abstract:
The possibilities of Sonic Crystals (SCs) as acoustic barriers have been intensively investigated during the last decade. A SC consists of a periodic array of scatterers embedded in a host fluid medium. These periodic structures provide a new wave control mechanism based on the structuring of the considered system, not on its acoustics properties. Perhaps, the most known property is the presence of the so-called band gaps (BG), defined as ranges of frequencies where the transmission of waves is forbidden inside the periodic structure. This property is used in finite structures to produce bands of frequencies of large transmission loss. However, both its central frequency and its width mainly depend on the geometry of the array being both angular dependent. Therefore, several strategies have been developed during last years to obtain acoustic screens based on SC with better performance. Basically, the path has been twofold: (i) seeking different arrangements of scatterers or (ii) bringing additional noise control mechanisms to both achieve high attenuation bands in the low frequency regime and to enhance as well as stabilize the attenuation capacity of these devices in a broad range of frequencies. Following this second strategy, we present in this work the design and manufacturing process of a prototype of SC noise barrier based on a triangular array of resonant absorbent scatterers. In order to compare the performance of our barrier with respect to the current ones, we have applied the European standards relative to road traffic noise reducing devices (EN 1793 (-1;-2;-3): 1997) to our prototype. Although these standards are not appropriate for our barrier, the obtained results are promising, revealing the SC acoustic barrier as a good alternative to the current devices under the acoustic perspective.