A Structural Health Monitoring Approach based on Contact Acoustic Nonlinearity and Its Application to Quantitative Evaluation of Fatigue Cracks
Abstract »A damage characterization approach was developed, by exploiting the second harmonics generated owing to the interaction between incident Lamb waves and a “breathing” crack. The approach was then expanded to deployment of a structural health monitoring method, whereby fatigue cracks in a plate-like structure can be evaluated quantitatively. A dedicated analytical model, in conjunction with the use of an elasto-dynamic reciprocity method, was established. Using the model, insight into the modulation mechanism of the crack on Lamb wave propagation was achieved, and the contact acoustic nonlinearity (CAN)-induced second harmonic generation, when Lamb wave traversing the “breathing” crack, was interrogated. Two scenarios were considered, in which a “breathing” crack was existent in the interior and edge of the plate, respectively, yielding a quantitative correlation between crack parameters and second harmonic-based nonlinearity. Results obtained from the proposed approach were compared with those from finite element simulation, to observe good coincidence. Limitation and initiatives for further improvement of the approach are also discussed.
Affiliation: The Hong Kong Polytechnic University Hong Kong Hong Kong, ChinaSu, Zhongqing*Su, Zhongqing* email@example.com 85227667818
Biography: Zhongqing Su earned his Ph.D. degree from the School of Aerospace, Mechanical and Mechatronic Engineering at the University of Sydney, Australia. He is now a Professor with the Department of Mechanical Engineering, The Hong Kong Polytechnic University. He is the author/co-author of two monographs, six edited books, four book chapters, and over 200 refereed papers. He was awarded the Structural Health Monitoring – Person of the Year (SHM-POY) in 2012. His research interests include structural health monitoring, wave propagation, smart materials and structures, sensors and sensor network. http://www.mypolyuweb.hk/mmsu/
Affiliation: The Hong Kong Polytechnic University Department of Mechanical Engineering 00000 Hong Kong Hong Kong, China