Calculation of diffraction coefficients for ultrasonic interactions at a right-angled corner

Summary form only given. A partial model has been developed for calculating the far-field effects of the interaction of an ultrasonic pulse with a flaw. This model uses finite differences to calculate the displacements on the flaw surface, and then an integral formulation to obtain the signals at any other point. Comparisons have been made with the results of calculations using other methods (simple finite difference, Kirchhoff approximation, geometrical theory of diffraction) in conditions where they are known to be valid and excellent agreement obtained. The model has also been used to obtain diffraction coefficients for the scattering of an ultrasonic pulse from a right-angled corner. This is a canonical problem in elastic theory, and also forms the basis for the calculation of the scattering from a flat-bottomed hole, often used as a calibration reflector. Comparisons have been made with measurements, both for compression waves and shear waves, and good agreement obtained in amplitude and phase