Development of a PC-Based Signal Processing Unit for Nondestructive Testing: The ALC and Small Angle B-Scan Techniques

摘要

When ultrasonic waves are reflected from acoustic discontinuities in materials, the shape of these echoes remains basically the same. The amplitudes and the arrival times of these pulses, however, will vary. Accordingly, to characterize the location and the severity of the flaws, one only needs to describe each reflected echo by two representative parameters: the time-of-flight values and the maximum amplitudes of the reflected echoes. Making use of the special characteristics of these two parameters, new testing procedures are introduced in this study to size flaws that are parallel to the sample surface and to detect defects in acoustically noisy materials.