A structural health monitoring approach based on contact acoustic nonlinearity and its application to quantitative evaluation of fatigue cracks

Kai Wang, Zhongqing Su

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review


A damage characterization approach was developed in this study by exploiting the second harmonics generated owing to the interaction between incident Lamb waves and a "breathing" crack. The approach can be expanded to deployment of structural health monitoring, whereby fatigue cracks in a plate-like structure can be evaluated quantitatively. A dedicated analytical model, in conjunction with the use of a variational principle-based method and an elasto-dynamic reciprocity method, was established. Using the model, an insight into the modulation mechanism of the crack on Lamb wave propagation was achieved, and the contact acoustic nonlinearity (CAN)-induced second harmonic generation was interrogated. Two scenarios were considered in which the plate bearing a "breathing" crack was modelled in two-dimensional and three-dimensional scenarios, respectively, yielding a quantitative correlation between crack parameters and second harmonic-based nonlinearity index. Results obtained from the proposed approach were compared with those from finite element simulation, to observe good coincidence.
Original languageEnglish
Title of host publication8th European Workshop on Structural Health Monitoring, EWSHM 2016
Number of pages10
ISBN (Electronic)9781510827936
Publication statusPublished - 1 Jan 2016
Event8th European Workshop on Structural Health Monitoring, EWSHM 2016 - Bilbao, Spain
Duration: 5 Jul 20168 Jul 2016


Conference8th European Workshop on Structural Health Monitoring, EWSHM 2016


  • Contact acoustic nonlinearity (CAN)
  • Fatigue crack
  • Second harmonic generation
  • Structural health monitoring.

ASJC Scopus subject areas

  • Health Information Management
  • Computer Science Applications

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