Recent Developments in Theoretical and Experimental Investigations with Ultrasonic Sensors

摘要

For several decades ultrasonic actuators and sensors have been used for nondestructive evaluation and structural health monitoring.In traditional applications longitudinal and shear bulk waves are sent into the structure and the reflected and/or transmitted signals are analyzed for detecting internal anomalies like cracks,inclusions,impurities and other defects.Guided waves have both longitudinal and shear components and propagate through waveguides like plates,rods and cylinders.Material inspection by guided waves is a relatively new technology although body waves have been used for this purpose for decades.Because of some inherent advantages of guided waves over the bulk waves,such as their long distance propagation potential,capability of reaching difficult-to-reach regions,and multi-mode propagation characteristics the guided wave based inspection techniques are gaining popularity.To exploit the full potential of this technology good theoretical analyses of guided wave propagations in various structures along with experimental investigations are necessary.Some of the recent advances in analyses and experiments on the guided wave propagation for civil infrastructure health monitoring applications will be discussed in this paper.