Rayleigh Wave Nondestructive Evaluation for Defect Detection and Materials Characterization

Numerical study of Rayleigh wave interaction with wedge geometry

“…The numerical TOF of the reflected wave mode can be calculated using DT num = t 3t 1 , where t 3 is the time corresponding to the maximum amplitude A r of the reflected wave shown in Figure 2a. The theoretical TOF of the transmitted wave can be determined by calculating the distance of the incident Rayleigh mode x 1 to the discontinuity D1, then to the transmitted mode x 2 shown in Figure 4 using DT th = (x 1 + x 2 )/V r , where V r is the Rayleigh wave velocity [7,42] for a given material. The difference in the theoretical and numerical TOF: DT = DT num À DT th , will be proportional to the change in the phase, which can be calculated using:…”

“…Surface or Rayleigh wave interaction with an elastic wedge is one of the interesting and unsolved classical problems in the geophysics and acoustics area [1][2][3][4][5][6]. Rayleigh surface waves can propagate only along the stress-free boundary of a half-space, with their energy confined to the sub-surface and decaying exponentially along the outof-plane direction [7][8][9][10][11][12]. Rayleigh wave interaction with discontinuities can produce mode conversions which will result in the transmission, reflection and scattering of the incident energy.…”

“…Rayleigh wave interaction with discontinuities can produce mode conversions which will result in the transmission, reflection and scattering of the incident energy. This interaction has been of significant interest to several communities including geophysics, acoustics and nondestructive evaluation [3,7,[12][13][14][15]. Rayleigh wave propagation and interaction with a wedge like discontinuity can be simplified as two ends of an elastic boundary that meet at a non-orthogonal angle while satisfying stressfree boundary conditions.…”