Obtaining flaw images that take the effect of multiple ultrasonic pulse reflections from the boundaries of a test object into account |
| |
Authors: | E G Bazulin |
| |
Affiliation: | 1.OOO Scientific and Production Center EKhO+,Moscow,Russia |
| |
Abstract: | The problem of obtaining flaw images from echo signals multiply reflected from the boundaries of a test object and modifications
of the FT-SAFT and SAFT algorithms for obtaining flaw images in a test object with plane-parallel boundaries are considered.
The reason that a transducer operating on transverse waves in the transceiver mode cannot yield information on flaw location
depth is stated. It is shown that the detecting signals in the double-scanning mode, obtaining a set of partial images by
the SAFT method, and combining them into a final image allow one to solve this problem. To obtain a combined image, the moduli
of partial images were summed and their median was calculated. Because of difficulties in determining the velocity of sound
and the thickness of a particular object, the coherent summation, which is potentially the most efficient combining technique
among the considered ones, does not allow one to obtain a high-quality image. The results of a numerical simulation of the
procedure of obtaining images of point defects are presented. The results of model experiments aimed at obtaining an image
of a 1-mm-deep groove in a 20-mm-thick metal slab are presented as well. It is shown that measuring echo signals in the double-scanning
mode and obtaining images by the DS-M-SAFT method make it possible to determine the flaw location depth. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|