Orienting fatigue cracks using contact acoustic nonlinearity in scattered plate waves

Kai Wang, Zheng Fan, Zhongqing Su

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)


Targeting quantitative delineation of nonlinear scatterers in elastic media and undersized fatigue cracks in particular, the present study is dedicated to investigation, from analytical, numerical, and experimental perspectives, of the underlying mechanism of interaction between guided ultrasonic waves (GUWs) and 'breathing' fatigue cracks - a representative nonlinear scatterer type. Under the modulation of probing GUWs, a 'breathing' crack scatters GUWs, in which the crack-triggered contact acoustic nonlinearity (CAN) is embodied. Analytical modeling demonstrates that the extracted CAN manifests unique scattering patterns associated with the crack slant, on which basis the crack can be oriented, without requiring reference to baseline signals. Experimental validation corroborates analytical prediction, in which an embryonic fatigue crack in an aluminum plate waveguide is oriented accurately and visualized in a pixelated image.

Original languageEnglish
Article number09LT01
JournalSmart Materials and Structures
Issue number9
Publication statusPublished - 10 Aug 2018


  • 'breathing' fatigue crack
  • contact acoustic nonlinearity
  • crack orientation
  • nonlinear scatterer

ASJC Scopus subject areas

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering


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