Reflection and transmission behaviors of ultrasonic wave at nano-air gap examined using Newton's ring specimen

Masaki Inoue, Tsuyoshi Mihara, Hatsuzou Tashiro, Takashi Furukawa

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Although in previous studies were examined the ultrasonic reflection behaviors at a nano-air gap using a relatively small optical Newton's ring specimen and a commercial acoustic lens, the details of the quantitative ultrasonic behaviors at a nano-air gap have remained unqualified until now. Since the accuracy of estimating these behaviors is directly related to the accuracy of industrial ultrasonic crack sizing, we tried to measure more accurately quantitative ultrasonic behaviors at a nano-air gap in this study. For this purpose, a special highly focused acoustic lens was designed and fabricated and applied to a large optical Newton's ring specimen to obtain accurate and reliable experimental results. Comparisons between the experimental and the conventional small gap theoretical results for a nano-air gap were also carried out. As a result, ultrasonic transmission was found to begin to occur from 60-70nm air gaps in all the measurements. This finding was largely different from that based on the gap theory. Regarding the cause of this large difference between the experimental and theoretical results, we also examined the influence of the surface roughness of contact plates.

Original languageEnglish
Article number07GB12
JournalJapanese journal of applied physics
Volume51
Issue number7 PART2
DOIs
Publication statusPublished - 2012 Jul 1
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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