Ultrasonic Guided Waves for NDE of Sign Support Structures

摘要

Ultrasonic guided waves (UGWs) are particular effective in those NDE and structural health monitoring (SHM) applications that can benefit from built-in transduction, moderately large inspection ranges and high sensitivity to small flaws. This paper describes a method based on UGWs devoted to the detection of cracks in sign support structures, which can be found along any major highway across the United States. The method combines the advantages of UGWs and signal processing to extract defect-sensitive features aimed at performing a multivariate diagnosis of damage. The general framework presented in this paper is applied to ultrasonic data collected from a dismantled overhead sign structure tested at the University of Pittsburgh. The probing hardware consists of a National Instruments-PXI platform that controls the generation and detection of the ultrasonic signals by means of piezoelectric transducers made of lead zirconate titanate. The effectiveness of the proposed approach to diagnose the presence of an artificial defect is demonstrated.