<p>The attenuation behaviour of Rayleigh waves as they propagate over a rough surface is a phenomenon which has been studied in depth theoretically. Past studies have identified three scattering regimes – the Rayleigh (long wavelength), stochastic (long to medium wavelength) and geometric (short wavelength) regimes. Mathematical expressions have been derived in each of these regimes, linking the behaviour of the attenuation coefficient to the surface’s statistical parameters, namely the RMS height and the correlation length, and the Rayleigh wave’s frequency. This study uses high-fidelity, two-dimensional finite element (FE) modelling to validate the existing theory under a unified approach, since the same FE model can be used to obtain an attenuation coefficient value, regardless of the scattering regime. Additionally, this study extends theory by obtaining attenuation coefficient values from roughness parameter combinations which are outside the limits of the current theory. Very good agreement has been found between the FE results and the theoretical behaviour of the attenuation coefficient, both in absolute and in asymptotic terms, in the Rayleigh and stochastic regimes. In the geometric regime, where the literature is more limited, some useful asymptotic results were obtained by combining the existing theory, dimensional analysis, and FE results.&nbsp; The results from this study also provide useful insight for the behaviour of the attenuation coefficient in three dimensions, as the mathematical methods used to derive the theory in three-dimensional theory are analogous to the two-dimensional case.</p>

A Study of Rayleigh Wave Attenuation Due to Surface Roughness

Paper Proceedings: https://asmedigitalcollection.asme.org/qnde/QNDE2021/volume/85529

ASME 2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.