Super-shear evanescent waves imaged at a solid-liquid interface

APR 01, 2022

Using a custom imaging setup, researchers observed a super-shear elastic surface wave at a solid-liquid interface for the first time and found strong confirmation of a non-leaky Rayleigh wave.

Mara Johnson-Groh

DOI: 10.1063/10.0010113

Super-shear evanescent waves imaged at a solid-liquid interface internal name — Super-shear evanescent waves imaged at a solid-liquid interface lead image

Over a decade ago, researchers discovered a wave that travels between the shear wave and the pressure wave along a free surface. Called super-shear evanescent waves, or SEW, these waves have been studied theoretically and experimentally ever since. Now, Nguyen et al. extended that work to SEWs at the interface of a solid and a liquid.

Using a custom-designed pump and probe imaging technique, the team captured whole-field images of elastic surface waves propagating along the interface of water and an epoxy resin surface. The elastic surface waves were induced by focusing a nanosecond pulsed laser beam on the interface. By imaging at specific time delays, the authors reconstructed the evolution of the waves and calculated their speeds.

“In general, a SEW is hard to detect because it may not separate from the Scholte and Rayleigh waves until propagating some distance from its source,” said author Thao Thi Phuong Nguyen. “But by using our custom-designed photoelasticity imaging technique, we were able to detect all surface waves excited at the nearfield of the laser focal point, with special attention to detecting SEW at a solid-liquid interface.”

The images showed SEWs and strong evidence of a non-leaky Rayleigh wave, marking the first time these waves have been seen directly and visually at a soft solid-liquid interface. The findings contribute to the understanding of elastic surface waves, which have applications in seismology, engineering, and nondestructive testing.

“We hope the results presented in this paper will attract more researchers to develop practical applications of the laser-excitation of elastic surface waves in an in-liquid regime,” Nguyen said.

Source: “Rayleigh wave and super shear evanescent wave excited by laser-induced shock at a soft solid-liquid interface observed by photoelasticity imaging technique,” by Thao Thi Phuong Nguyen, Rie Tanabe-Yamagishi, and Yoshiro Ito, Journal of Applied Physics (2022). The article can be accessed at https://doi.org/10.1063/5.0081237 .

This paper is part of the Shock Behavior of Materials Collection, learn more here .