Effects of periodicity perturbations on the transmission by underwater phononic crystals
K. Zong, H. Franklin and O. Lenoir
Laboratoire Ondes et Milieux Complexes UMR CNRS 6294, Universite du Havre, Place R. Schuman BP 4006, 76610 Le Havre, France
M. V. Predoi
Department of Mechanics, University Politehnica Bucharest, Splaiul Independentei 313, Bucharest, Romania
(Received 13 December 2011; revised 13 July 2012; accepted 17 July 2012)
Abstract
The effects of periodicity perturbations in underwater phononic crystal layers composed of noninterpenetrating rows of identical shells are investigated. The results for one row are obtained by
using a multiple scattering method between shells. Then, taking into account the multiple reflections
and transmissions between two adjacent rows, a Debye series method is used to calculate the
reflection and transmission coefficients by a finite number of rows. The paper focuses on three
kinds of perturbations: (i) variation of the inner radius of shells from row to row, (ii) increase in
the spacing from row to row and of the number of rows, and (iii) substitution of simple steel rows
by steel-polyethylene bilayers. It is shown by studying the transmission coefficient that the case
(i) permits the insertion of narrow pass bands in the stop band while the two other cases (ii) and
(iii) widen the stop band. The study intends to model simple underwater acoustic filters.
VC 2012 Acoustical Society of America. [http://dx.doi.org/10.1121/1.4744976]
PACS number(s): 43.35.Gk, 43.50.Gf, 43.40.Fz, 43.20.Fn [ANN] Pages: 2834–2841
Journal of the Acoustical Society of America, vol. 132(4), pg. 2834–2841, (ISSN: 0001-4966)