scholarly journals Diffraction of elastic waves by edges

2018 ◽  
Vol 68 (4) ◽  
pp. 1447-1517
Author(s):  
Vitaly Katsnelson
1963 ◽  
Vol 59 (1) ◽  
pp. 231-248 ◽  
Author(s):  
Iya Abubakar

AbstractThis is a continuation of (1) on the two-dimensional problem of the diffraction of elastic waves by irregular surfaces. The effect of an irregular surface with an isolated irregularity like a trough or ditch on incident plane harmonic P- and SV-waves is discussed. The maximum depth of the ditch is assumed small compared to the wavelength of the incident wave.It is found that, when either a P- or an SV-wave is incident on such a boundary, besides the specularly reflected P- and SV-waves whose amplitudes are independent of the curvature of the surface there exist scattered waves travelling in various directions. In particular the diffracted zone contains the following second wave-types whose amplitudes are proportional to the depth of the ditch: (i) direct reflected P- and SV-waves, which at large distances appear to diverge from the point of intersection of the axis of symmetry of the ditch and the horizontal plane asymptotic to the boundary if the ratio of the wavelength of the incident wave to the half-width of the ditch is large. If the ratio is small these waves are reflected in the specular directions, (ii) A ‘secondary S-wave’ which finishes as P having travelled most of the way as an SV-wave. Its energy is confined to the neighbourhood of the free surface, (iii) A secondary P-wave which travels along the surface and finally emerges into the medium as an SV-wave at the critical angle for the medium, (iv) Rayleigh waves whose particle motion is in elliptic orbits.


1961 ◽  
Vol 51 (1) ◽  
pp. 35-49
Author(s):  
Leon Knopoff ◽  
Freeman Gilbert

Abstract The problem of the diffraction of a seismic pulse by the core of the Earth is investigated theoretically. The result is compared to that of diffraction by a half-plane. The differences are striking. Laboratory model experiments have been performed to verify the theoretical approximations in their regions of validity, and to complement the theory elsewhere. The curves, thus obtained, of the theoretical amplitude distribution in the shadow of the Earth's core agree very well with the observations of Gutenberg. It is therefore concluded that diffraction is a completely adequate explanation for the amplitude distribution in the shadow zone.


2014 ◽  
Vol 526 ◽  
pp. 145-149 ◽  
Author(s):  
Li Wang ◽  
Pei Jun Wei ◽  
Xi Qiang Liu ◽  
Gui Zhang

Diffraction of in-plane wave and out-plane wave by a cylindrical nanohole is investigated. The surface elastic theory is used to consider the surface stress effects and to derive the boundary condition on the surface of the nanohole. The plane wave expansion method is applied to obtain the scattering waves. The scattering cross section and far-field scattering amplitude are numerically evaluated. The influences of surface stress are discussed based on the numerical results.


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