Angular and frequency spectral analysis of the ultrasonic backward beam displacement on a periodically grooved solid

Abstract

The ultrasonic backward beam displacement, which has been shown to occur when a bounded beam is incident upon a periodically corrugated liquid-solid interface, is studied experimentally. This effect has been previously studied on a periodic water-brass interface at one particular frequency (6 MHz) and one corresponding angle of incidence (22.5 degrees), but the question has remained whether it would also exist at other frequency and angle combinations. The knowledge of whether this phenomenon is a coincidence or whether it will occur for other frequency and angle combinations contributes to a better understanding of the interaction of ultrasound with periodic structures and diffraction effects, in particular. Potential applications exist in the study of phononic crystals and in the non-destructive evaluation of materials. The present work reports results from recent experiments on the same periodically grooved brass sample that was employed in the first investigations of this phenomenon. Through the examination of frequency spectra in the form of angular and classical spectrograms, the experiments reported here show the backward beam displacement to occur for multiple angles of incidence and frequencies. Furthermore, evidence is shown as to the exact cause of the backward beam displacement, namely, a backward propagating Scholte-Stoneley wave.

Observation of ultrasonic backward beam displacement in transmission through a solid having superimposed periodicity

“…However, it has been recently shown that pulsed ultrasonic beams also experience the phenomenon in the form of backward shifted frequency components. 2 In addition, spectrograms have revealed that these frequency components continue to radiate into the fluid well after the specularly reflected beam has passed. Since the backward displacement phenomenon has only been observed in reflection, the question has remained whether it can also be observed in transmission through a solid, since the energy of the leaky Scholte-Stoneley wave that is responsible for the displacement is mostly confined to the liquid side of the corrugated interface.…”

“…1,2 This assumption is based on a nondispersive nature of such surface waves, which may not be fully accurate and requires further study. In addition, although this study examined transmission of shear waves through the solid sample, the insight gained implies that a backward propagating Scholte-Stoneley wave generated for a certain frequency on a periodically corrugated surface may result in a backward shift for that frequency in all fields generated.…”

The Schoch effect mechanism analysis and its regulation of two dimensional three components phononic crystal

“…2004年, Declercq等人 [39] 进一步发 展了非均匀波衍射理论在负向Schoch位移的声学衍射 研究, 研究结果表明Schoch位移的产生与类斯通利波 的产生有着密切关系. 2009年, Herbison等人 [40] 采用脉 冲波代替时域谐波的新实验方法定量测量了Schoch位 移的大小. 2014年, Declercq [41] 响 [43] , 因此本文利用有限元方法计算的二维声子晶体 第一能带的等频线 [20] 来确定自准直频率, 其中频率相 http://engine.scichina.com/doi/10.1360/SSPMA2016-00475…”

Schoch Effect in Topological Phononic Crystals

“…In 2004, Declercq et al extended the theory of non-uniform wave diffraction to acoustic diffraction with negative Schoch displacement [5], The research results indicate that the Schoch effect is closely related to the generation of interface Stoneley waves. In 2009, Herbison et al developed a new method using pulse waves instead of harmonic waves in time domain to quantitatively measure the Schoch displacement [6]. In 2014, Declercq conducted experimental research on the energy conversion of ultrasound waves when Schoch displacement occurred [7].…”