Nonlinear guided waves are sensitive to small-scale fatigue damage that may hardly be identified by traditional techniques. A characterization method for fatigue damage is established based on nonlinear Lamb waves in conjunction with the use of a piezoelectric sensor network. Theories on nonlinear Lamb waves for damage detection are first introduced briefly. Then, the ineffectiveness of using pure frequency-domain information of nonlinear wave signals for locating damage is discussed. With a revisit to traditional gross-damage localization techniques based on the time of flight, the idea of using temporal signal features of nonlinear Lamb waves to locate fatigue damage is introduced. This process involves a time-frequency analysis that enables the damage-induced nonlinear signal features, which are either undiscernible in the original time history or uninformative in the frequency spectrum, to be revealed. Subsequently, a finite element modeling technique is employed, accounting for various sources of nonlinearities in a fatigued medium. A piezoelectric sensor network is configured to actively generate and acquire probing Lamb waves that involve damageinduced nonlinear features. A probability-based diagnostic imaging algorithm is further proposed, presenting results in diagnostic images intuitively. The approach is experimentally verified on a fatigue-damaged aluminum plate, showing reasonably good accuracy. Compared to existing nonlinear ultrasonics-based inspection techniques, this approach uses a permanently attached sensor network that well accommodates automated online health monitoring; more significantly, it utilizes time-domain information of higher-order harmonics from time-frequency analysis, and demonstrates a great potential for quantitative characterization of small-scale damage with improved localization accuracy.
|Title of host publication||Proceedings of SPIE: Health Monitoring of Structural and Biological Systems 2014|
|Place of Publication||Bellingham Washington DC USA|
|Number of pages||13|
|Publication status||Published - 2014|
|Event||SPIE Smart Structures and Materials and Non-destructive Evaluation and Health Monitoring 2014 - Town and Country Resort Hotel & Convention Center, San Diego, United States of America|
Duration: 10 Mar 2014 → 13 Mar 2014
|Conference||SPIE Smart Structures and Materials and Non-destructive Evaluation and Health Monitoring 2014|
|Country/Territory||United States of America|
|Period||10/03/14 → 13/03/14|
|Other||Please use the following format to cite material from this book:|
Author(s), "Title of Paper," in Health Monitoring of Structural and Biological Systems 2014, edited by
Tribikram Kundu, Proceedings of SPIE Vol. 9064 (SPIE, Bellingham, WA, 2014) Article CID Number.