Analysis of Inverse Problem for Sizing Closed Vertical Crack by Ultrasonics

Masumi Saka, Shigeo Takita

Research output: Contribution to journalArticlepeer-review


Ultrasonic testing using a normal incident longitudinal wave is treated for sizing a closed crack. The crack exists vertically on the back wall of a plate inspected. Reflection and transmission of the wave at the closed crack surfaces are analysed by introducing a model of crack closure. The model includes a stress closing the crack and a phase shift of the reflected and trasmitted waves as unknown parameters. The unknown parameters have been determined together with the unknown length of the crack by analysing the inverse problem, which compares the back-wall echo height obtained through both theory and experiment. Two kinds of cracks introduced by different stress ratio in fatigue have been examined. The ultrasonic measurements for specimens have shown that the present analysis offers a powerful tool for precise sizing of closed vertical crack.

Original languageEnglish
Pages (from-to)2395-2402
Number of pages8
JournalTransactions of the Japan Society of Mechanical Engineers Series A
Issue number542
Publication statusPublished - 1991


  • Crack
  • Crack Closure
  • Inverse Problem
  • Nondestructive Inspection
  • Ultrasonic Inspection

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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