Numerical simulation and experimental verification of ultrasonic wave radiation and diffraction by crack-like flaws

The modelling of ultrasonic fields in the presence of flaws in materials is of great interest to researchers in the area of non-destructive testing and evaluation (NDT&E). In this work, we provide an efficient method to model ultrasonic wave fields generated by a transducer of finite size in materials and scattered by internal crack-like flaws. The incident wave fields generated by the transducer and the wave fields scattered by and diffracted through the flaws are modelled using the Rayleigh integral expression and calculated using a Quasi-Monte Carlo (QMC) method. Since this method does not require assumptions for approximating the geometry of flaws or wave propagation, it is applicable to area flaws with complex geometries or even volumetric flaws, as long as the surfaces of these flaws can be accurately constructed. The effects of flaw sizes, curvatures, and inclination angles on the wave fields diffracted through crack-like flaws are investigated. The provided simulation results are verified both theoretically and experimentally. The proposed method, characterised by its high efficiency and accuracy, provides valuable insights into wave propagation in materials containing internal crack-like defects, facilitating the quantitative assessment of these defects.