Ultrasonic inspection, material noise and surface roughness.

摘要

The phase-screen approximation (PSA) can be used to model interaction of ultrasound with rough surfaces if the height variation is small and correlation length is large relative to wavelength. Material noise is enhanced for early times and decreased for late times. PSA can calculate ultrasound transmission through random rough surfaces; as a numerical method, it will be most appropriate for complicated m=problems such as rough curved surfaces, where the Boundary Integral Equation is too time-consuming. PSA can serve as a starting point for analyzing the physics of transmission through rough surfaces. However, it needs corrections to the amplitude of the transmitted wave. Nonetheless, it can serve as the basic engineering model for the effects of surface roughness on ultrasonic inspections.