Detection of cracks in plates and pipes using piezoelectric materials and advanced signal processing technique

Abstract

The main objective of this research is to devise and experimentally illustrate a methodology for non-destructive evaluation (NDE) of plate and cylindrical structures using time-of-flight (TOF) analysis of Lamb wave propagation in the structures. The major problem in NDE of structures using Lamb wave for ultrasonic inspection is dispersion which complicates the analysis of the wave signals and makes the precise localization of defects difficult. The major scope of this study include: (a) the investigation of exciting suitable Lamb wave mode(s) for efficient NDE of thin plates and pipes using piezoelectric material; (b) the design of a comprehensive procedure for the detection and localization of cracks in plates and pipes based on TOF analysis of Lamb wave using Hilbert-Huang transform (HHT) as the signal processing technique for accurate identification of localized events in time; and (c) the exploration of frequency response functions (FRF) information to isolate the inspection for the case of large structural components.