Absolute Magnitude of Front Surface Reflections in Ultrasonic Measurements

Abstract

It has been shown in other papers in this volume (1,2) that the application of deconvolution, diffraction, and attenuation corrections to received ultrasonic signals is sufficient to extract the absolute value of the flaw scattering amplitude from the signal. This capability provides a new opportunity to obtain additional flaw characterization information from the ultrasonic signal. More specifically, it is postulated upon reasonable grounds that the absolute magnitude of the front surface ultrasonic echo from a flaw can be related to both the flaw dimensions and its acoustic impedance. Assuming that the size can be obtained by other means, the front surface echo can then be utilized to help identify the flaw. The purpose of this paper is thus twofold: 1) to utilize the diffraction and attenuation corrections developed by Thompson and Gray (3) to obtain absolute values of flaw impulse responses, and 2) to investigate the feasibility of using absolute values of front surface echoes to determine a flaw’s identity.