Extracting the Subsonic Anti-Symmetric Lamb Wave from a Submerged Thin Spherical Shell Backscattering Through Iterative Time Reversal

作     者：YU Xiaotao PENG Linhui YU Gaokun 

作者机构：School of Information Science and Engineering Ocean University of China State Key Laboratory of Acoustics Chinese Academy of Sciences 

出 版 物：《Journal of Ocean University of China》 (中国海洋大学学报（英文版）)

年 卷 期：2014年第13卷第4期

页      面：589-596页

核心收录：

学科分类：082403[工学-水声工程] 08[工学] 0824[工学-船舶与海洋工程] 

基　　金：supported by the National Natural Science Foundation of China (46976019) the open project of the State Key Laboratory of Acoustics, Chinese Academy of Sciences (SKLA201202) 

主　　题：backscattering Lamb wave time reversal frequency of greatest enhancement SNR 

摘      要：The extraction of the weakly excited anti-symmetric Lamb wave from a submerged thin spherical shell backscattering is very difficult if the carrier frequency of the incident short tone burst is not at its frequency of greatest enhancement. Based on a single channel iterative time reversal technique, a method for isolating the subsonic anti-symmetric Lamb wave is proposed in this paper. The approach does not depend on the form function of a thin shell and any other priori knowledge, and it is also robust in the presence of some stochastic noise. Both theoretical and numerical results show that the subsonic anti-symmetric Lamb wave can be identified, even when the carrier frequency of the incident short tone burst is away from the frequency of greatest enhancement. The phenomenon may also be observed even in the case that the subsonic anti-symmetric Lamb wave is submerged in the noise, other than the case with the Signal to Noise Ratio being less than 10 d B, when the amplitude of the noise is comparable with the specular wave. In this paper, each iteration process contains a traditional transmission and time reversal transmission steps. The two steps can automatically compensate the time delay of the subsonic anti-symmetric Lamb wave relative to the specular wave and within-mode dispersion in the forward wave propagation.