Ultrasonic inspection of studs (bolts) using dynamic predictive deconvolution and wave shaping

Citation
Dm. Suh et al., Ultrasonic inspection of studs (bolts) using dynamic predictive deconvolution and wave shaping, IEEE ULTRAS, 46(2), 1999, pp. 457-463
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Optics & Acoustics
Journal title
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
ISSN journal
0885-3010 → ACNP
Volume
46
Issue
2
Year of publication
1999
Pages
457 - 463
Database
ISI
SICI code
0885-3010(199903)46:2<457:UIOS(U>2.0.ZU;2-D
Abstract
Bolt degradation has become a major issue in the nuclear industry since the 1980's. If small cracks in stud bolts are not detected early enough, they grow rapidly and cause catastrophic disasters. Their detection, despite its importance, is known to be a very difficult problem due to the complicated structures of the stud bolts. This paper presents a method of detecting an d sizing a small crack in the root between two adjacent crests in threads. The key idea is from the fact that the mode-converted Rayleigh wave travels slowly down the face of the crack and turns from the intersection of the c rack and the root of thread to the transducer. Thus, when a crack exists, a small delayed pulse due to the Rayleigh wave is detected between large reg ularly spaced pulses from the thread. The delay time is the same as the pro pagation delay time of the slow Rayleigh wave and is proportional to the si ze of the crack. To efficiently detect the slow Rayleigh wave, three method s based on digital signal processing are proposed: wave shaping, dynamic pr edictive deconvolution, and dynamic predictive deconvolution combined with wave shaping.