MULTI-ELEMENT LAMB WAVE TRANSDUCERS TO CLASSIFY DAMAGE TYPE AND CHARACTERIZE SIZE BASED ON MODAL CONTENT

摘要

Assessing the structural integrity of PVP systems entails a hierarchical process to detect, locate, classify, and size damage in order to predict the remaining useful life of the system. Technologies to detect and locate damage have been researched intensely over the years, but classification and sizing of damage remains a challenging problem. In this work advanced sensing technology is employed to send and receive Lamb waves in plates. The receiver is a 16-element linear array that is made from PVDF; thus it is lightweight, low profile, flexible, inexpensive, and has minimal cross talk. The receiver has two novel capabilities that open new opportunities in diagnostics and prognostics: measurement of group velocity and determination of modal content. The actuator and receiver are intended to stay in place and function in a pitch-catch mode. The use of modal content to classify the type of damage as well as to size the defect is demonstrated.