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An exhaustive study has been made into the potential improvement in attenuation and focusing of phononic crystal arrays resulting from the deliberate creation of vacancies. Use is made of a stochastic search algorithm based on evolutionary algorithms called the epsilon variable multi-objective genetic algorithm which, in conjunction with the application of multiple scattering theory, enables the design of devices for effectively controlling sound waves. Several parameters are analyzed, including the symmetries used in the distribution of holes and the optimum number of holes. The validity and utility of the general rules obtained have been confirmed experimentally. ; This work was partially supported by MEC (Spanish Government) and FEDER funds: Project Nos. 419DPI2005-07835, and MAT2006-03097 and Generalitat Valenciana Project Nos. GV06/026 and 420 GV/2007/191. The authors would like to thank John Rawlins (associate member of the Institute of Translation and Interpreting (No. 9743) of UK, and "Certified PRO" of ProZ according to the EN 15038) for his help with the use of English. ; Romero García, V.; Sánchez Pérez, JV.; García Raffi, LM.; Herrero Durá, JM.; García Nieto, S.; Blasco, X. (2009). Hole distribution in phononic crystals: design and optimization. Journal of the Acoustical Society of America. 125(6):3774-3783. https://doi.org/10.1121/1.3126948 ; S ; 3774 ; 3783 ; 125 ; 6

2235021 2235023 93 22 ; S ; Copyright (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics along with the following message: The following article appeared in "Romero García, V.; Sánchez Pérez, JV.; García-Raffi, LM.; Herrero Durá, JM.; S. Garcia-Nieto; Blasco Ferragud, FX. (2008). High optimization process for increasing the attenuation properties of acoustic metamaterials by means of the creation of defects. Applied Physics Letters. 93:2235021-2235023" and may be found at http://dx.doi.org/10.1063/1.3040317. Authors own version of final article on e-print servers An improvement in the attenuation capabilities of acoustic metamaterials by means of the creation of defects is considered here as a multiobjective optimization problem. From this point of view, it is possible to define the optimum strategy in the creation of defects to achieve an important increase in acoustic attenuation in a predetermined range of frequencies. A powerful multiobjective optimization algorithm called evMOGA has been used to solve this problem. The study has been restricted to the case of a two-dimensional sonic crystal formed by rigid cylinders in air, the defects being vacancies in the initial structure. This work was partially supported by MEC (Spanish Government) and FEDER funds: Project Nos. 419DPI2005-07835 and MAT2006-03097 and Generalitat Valenciana Project Nos. GV06/026 and GV/2007/191. Romero García, V.; Sánchez Pérez, JV.; García-Raffi, LM.; Herrero Durá, JM.; García Nieto, S.; Blasco Ferragud, FX. (2008). High optimization process for increasing the attenuation properties of acoustic metamaterials by means of the creation of defects. Applied Physics Letters. 93(22):2235021-2235023. doi:10.1063/1.3040317 Fang, N., Xi, D., Xu, J., Ambati, M., Srituravanich, W., Sun, C., & Zhang, X. (2006). Ultrasonic metamaterials with negative modulus. Nature Materials, 5(6), 452-456. doi:10.1038/nmat1644 ...

Copyright (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics along with the following message: The following article appeared in "Romero García, V.; Sánchez Pérez, JV.; García-Raffi, LM.; Herrero Durá, JM.; S. Garcia-Nieto; Blasco Ferragud, FX. (2008). High optimization process for increasing the attenuation properties of acoustic metamaterials by means of the creation of defects. Applied Physics Letters. 93:2235021-2235023" and may be found at http://dx.doi.org/10.1063/1.3040317. Authors own version of final article on e-print servers ; An improvement in the attenuation capabilities of acoustic metamaterials by means of the creation of defects is considered here as a multiobjective optimization problem. From this point of view, it is possible to define the optimum strategy in the creation of defects to achieve an important increase in acoustic attenuation in a predetermined range of frequencies. A powerful multiobjective optimization algorithm called evMOGA has been used to solve this problem. The study has been restricted to the case of a two-dimensional sonic crystal formed by rigid cylinders in air, the defects being vacancies in the initial structure. ; This work was partially supported by MEC (Spanish Government) and FEDER funds: Project Nos. 419DPI2005-07835 and MAT2006-03097 and Generalitat Valenciana Project Nos. GV06/026 and GV/2007/191. ; Romero García, V.; Sánchez Pérez, JV.; García-Raffi, LM.; Herrero Durá, JM.; García Nieto, S.; Blasco Ferragud, FX. (2008). High optimization process for increasing the attenuation properties of acoustic metamaterials by means of the creation of defects. Applied Physics Letters. 93(22):2235021-2235023. https://doi.org/10.1063/1.3040317 ; S ; 2235021 ; 2235023 ; 93 ; 22 ; Fang, N., Xi, D., Xu, J., Ambati, M., Srituravanich, W., Sun, C., & Zhang, X. (2006). Ultrasonic metamaterials with negative modulus. Nature Materials, 5(6), ...