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2001 Fiscal Year Final Research Report Summary

Nondestructive evaluation of the initial surface damage of structural elements by using nonlinear surface wave

Research Project

Project/Area Number 10450047
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Materials/Mechanics of materials
Research InstitutionNagoya Institute of Technology

Principal Investigator

KAWASHIMA Koichiro  Nagoya Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50023239)

Co-Investigator(Kenkyū-buntansha) HAYASHI Takahiro  Nagoya Institute of Technology, Faculty of Engineering, Research associate, 工学部, 助手 (30324479)
ITO Toshihiro  Nagoya Institute of Technology, Faculty of Engineering, Associated Professor, 工学部, 助教授 (20203151)
Project Period (FY) 1998 – 2000
KeywordsUltrasonic / Nonlinear wave / Surface wave / Harmonics / Surface crack / Finite element method / Wave propagation / Semi-closed crack
Research Abstract

The purpose of this project is to establish an ultrasonic evaluation method of nearly closed shallow surface cracks with nonlinear surface wave. The project is composed of (a) the detection of the second harmonic of the leaky Rayleigh wave exited at nearly closed cracks with a line-focused surface wave sensor, and (b) numerical simulation of the nonlinear surface wave propagation by using FEM analysis in which contact elements are introduced to model nearly closed surface cracks.
Main results obtained by this project are summarized in the followings.
1) A nearly closed fatigue crack is detected by the second harmonic amplitude of the leaky Rayleigh wave of 5MHz. A line-focused PVDF sensor was used to transmit 5MHz incident wave to receive the second harmonic wave of 10MHz. The amplitude spectrum of the received waveforms identifies the second harmonic amplitude, by which the second harmonic amplitude ratio, 10MHz amplitude/5MHz amplitude, is evaluated.
2) By applying weak compressive stress to close the fatigue cracks, the second harmonic amplitude ratio shows marked change. Thus, fatigue cracks are identified.
3) FEM analyzes combined with contacts element to model nearly closed cracks simulate generation and propagation of the second harmonic wave excited at the cracks by the Rayleigh wave.
4) The second harmonic amplitude ratio of an inclined surface cracks is far smaller than that ofa perpendicular crack.
5) The second harmonic amplitude ratio is proportional to the crack depth up to a quarter of the surface wavelength, but it is saturated for deeper cracks over that depth.

  • Research Products

    (13 results)

All Other

All Publications (13 results)

  • [Publications] K.Kawashima, R.Omote, T.Ito, H.Fujita, T.Shima: "Nonlinear acoustic response through minute surface cracks : FEM simulation and experiment"Ultrasonics. 40/2(In press). (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] R.Omote, K.Kawshima, T.Ito: "Simulation of nonlinear Rayleigh wave propagation through minute surface cracks"Proc. 2001 IEEE Ultrasonic Symposium. (In press). (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] J.Okada, T.Ito, K Kawashima, N.Nishimura: "Finite element simulation of nonlinear acoustic behavior at minute cracks using singular element"Jpn. J. AppL Phys.. 40. 3579-3582 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 表, 川嶋, 伊藤: "表面斜め表面き裂を通過するレイリー波ノ非線形性"第9回超音波による非破壊評価シンポジウム. 61-62 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 島, 藤田, 下野, 川嶋: "非線形超音波を用いたコーティング膜模擬剥離検出"日本非破壊検査協会平成13年度春季大会講演会. 13-14 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K. Kawashima, R. Omote, T. Ito, H. Fujita, T. Shima: "Nonlinear acoustic response through minute surface cracks: FEM simulation and experiment"Ultrasonics. 40-2, (in press). (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] R. Omote, K. Kawshima, T. Ito: "Simulation of nonlinear Rayleigh wave propagation through minute surface cracks"Proc. 2001 IEEE Ultrasonic Symposium. in press. (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] J. Okada, T. Ito, K. Kawashima, N. Nishimura: "Finite element simulation of nonlinear acoustic behavior at minute cracks using singular element"Jpn. J. Appl. Phys.. 40-2. 3579-3582 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] R. Omote, K Kawashima, T. Ito: "Nonlinearity of Rayleigh wave past through inclined surface nearly closed crack(in Japanese)"Proc. 9th Symposium on Ultrasonic Testing Japanese Society for Nondestructive Inspection. 61-62. (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Kawashima, T. Omote, T. Ito: "Evaluation of semi-closed surface cracks with nonlinear ultrasonic wave (in Japanese)"Proc. JDNDI Fall Conference 2001 Japanese Society for Nondestructive Inspection. 9-10. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] R. Omote, T. Ito, K. Kawashima: "FEM simulation for detecting higher harmonics excited at semi-closed surface cracks (in Japanese)"Technical reports on ultrasonic testing #21659 Japanese Society for Nondestructive Inspection. 71-74. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Shima, H. Fujita, K. Kawashima: "Surface microcrack detection with nonlinear surface wave (in Japanese)"Proc. 8^<th> Symposium on Ultrasonic Testing Japanese Society for Nondestructive Inspection. 115-116. (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Kawashima, K. Nawa: "Detection of the second harmonic of longitudinal wave with large amplitude incident wave (in Japanese)"Proc. 6th Symposium on Ultrasonic Testing Japanese Society for Nondestructive Inspection. 57-58. (1999)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2003-09-17  

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