Scattering of Rayleigh surface waves by edge cracks: Numerical simulation and experiment

Scattering of Rayleigh surface waves by surface edge cracks is numerically simulated in a two‐dimensional geometry, using the finite‐difference method and the FFT algorithm. For shallow cracks, it is revealed that the transmission coefficient decreases with normalized depth h* = hc/λ and the reflection coefficient increases with h*, where hc is the crack depth and λ the wavelength. For relatively deep cracks, these coefficients appear to be independent of h*, while the time‐of‐flight of the transmitted Rayleigh wave linearly increases with h*. The numerical solutions are in good agreement with the experimental observations based on the ultrasonic spectrum analysis and the time‐of‐flight measurements for the artificial cracks in mild‐steel test pieces.