Sign Support Structures Tested by means of Guided Waves

Abstract

In the last few years the use of guided ultrasonic waves (GUWs) for the health monitoring of engineering structures increased rapidly, with the most recent studies focusing on the application of GUWs to complex structures or to simple structures under varying environmental conditions. Monitoring complex structures is challenging as reflections, scattering, and mode conversion arise. In addition, sensitivity to temperature and surface wetting can degrade the performance of a GUW-based structural health monitoring system. This paper presents the results of an experimental investigation where GUWs were used for the health monitoring of a truss, that was part of a highway variable message structure removed from service. The monitoring strategy proposed here combines the advantages of GUWs with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The effectiveness of the proposed approach was tested by monitoring the propagation of waves along one of the main chords of the truss and detecting the presence of two artificial cracks located around the welds that join two diagonal angular members to the chord.KeywordsHealth MonitoringDamage IndexUnsupervised Learning AlgorithmNotch SizeDiagonal MemberThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.