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Authors: Aditya Chilukuri (Indian Institute of Technology Madras) , Nishanth Raja (Indian Institute of Technology Madras) , Krishnan Balasubramaniam (Indian Institute of Technology Madras)
The use of ultrasonic guided waves has been identified as a promising technology for continuous monitoring of pipe structures to detect defects of cross-sectional area ratio less than 5%. This paper presents an effective approach to use torsional guided wave mode T(0,1) in thin and small diameter stainless steel tubes for detecting small pitting defects using magnetostriction sensors. The phenomenon of scattering of the fundamental torsional mode T(0,1) from complex-shaped discontinuities in thin tubes is closely examined, and its excitation parameters are optimized to an extent using finite element (FE) simulations. From the numerical and experimental results, the optimized design for transmitting/receiving pure torsional modes in cylindrical waveguides at high frequencies in the range of 1MHz are investigated. The results show that the reflection coefficient of torsional guided wave mode T(0,1) is a stronger function of the through-thickness depth as well as the axial and circumferential extent of the notch. The finite element results are then compared with the experimental data. The sensitivity of the reflected signal from defects up to 2% of the cross-sectional area ratio was examined, and it was found that defects smaller than 2% of the cross-sectional area ratio were detectable.This work is of great interest to many process industries including semiconductor manufacturing industries.
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How to Cite: Chilukuri, A. . , Raja, N. . & Balasubramaniam, K. . (2019) “Pitting corrosion detection in thin tubes using torsional guided wave mode T(0,1)”, Review of Progress in Quantitative Nondestructive Evaluation.(0).