The reflection of ultrasound from partially contacting rough surfaces

This paper describes an investigation into the combined effects of crack- face roughness and Closure on ultrasonic detectability. A contact model has been used to estimate the size and shape of scallerers (voids) at the interface of these rough Surfaces. Finite element analysis has been used to determine the response to excitation with a longitudinal ultrasonic pulse over a wide range of frequencies for different sizes. distribution,, and shapes of scatterers. Comparisons between the finite element predictions and experimental results have shown good a agreement.