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Indexed by:Journal Papers

Date of Publication:2016-01-01

Journal:MATERIALS EVALUATION

Included Journals:SCIE、Scopus

Volume:74

Issue:1

Page Number:79-89

ISSN No.:0025-5327

Key Words:pipeline inspection; ultrasonic guided waves; dent identification

Abstract:Dents are one of the primary failure modes in pipelines, and dent detection is a critical technology to ensuring pipeline safety. An experimental study for detection and identification of dents in pipes using ultrasonic guided waves was carried out. For revealing the relationship between the characteristics of reflected guided waves and the geometric features of dents, the dented region was represented by a series of circumferential cross-sections and a quantitative parameter; the so-called deformation rate was defined to evaluate the effect of the extent of the dent on the reflection. Both single- and double-sided dents were mechanically simulated in hollow aluminum pipes and then experimentally tested by exciting and receiving the longitudinal L(0,2) mode. The results show that the L(0,2) reflection coefficients from both types of dents increase monotonically with their respective deformation rates at all selected frequencies. The radial displacement of the L(0,2) mode may be a primary factor influencing the sensitivity of the dent detection. It is shown that the L(0,2) reflection coefficients decrease markedly at lower frequencies while decrease slightly at relatively high frequencies. Furthermore, the tendency of the curve of reflection coefficient with frequency is similar to that the radial displacement of the L(0,2) mode versus frequency. These characteristics indicate that the wideband L(0,2) mode provides a viable technique for detection and identification of dents in pipelines.