Evaluation of closed cracks by analysis of subharmonic ultrasound

Kazushi Yamanaka, Tsuyoshi Mihara, Toshihiro Tsuji

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Cracks in solids can be detected by ultrasound if they are open. However, their detection is not easy when they are closed with a closure stress. This is a fundamental problem in ultrasonic testing. Subharmonics ultrasound with half the input frequency is potentially useful in the detection and evaluation of such cracks. Analytical and numerical theories accounting for the crack parameters, such as closure stress and crack surface conditions, have been developed for the first time and their validity proved by comparison with experiments on a well-defined fatigue crack in aluminium alloy. Based on these theories, a novel method is proposed to estimate size of partially closed cracks, which solves the fundamental problem in ultrasonic testing.

Original languageEnglish
Pages (from-to)666-670
Number of pages5
JournalInsight: Non-Destructive Testing and Condition Monitoring
Issue number11
Publication statusPublished - 2004 Nov

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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