Autori: K. Zong, H. Franklin, O. Lenoir, M.V. Predoi
Editorial: Journal of the Acoustical Society of America, 132(4), p.2834-2841, 2012.
The effects of periodicity perturbations in underwater phononic crystal layers composed of nonin-
terpenetrating 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.
Cuvinte cheie: Acustica generala, Acustica ultrasonora // General acoustics, Ultrasonic acoustics