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Development of Crack Detection System on Structural Members

Research Project

Project/Area Number 09651012
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 船舶工学
Research InstitutionYokohama National University

Principal Investigator

ISHIZUKA Tetsuo  Yokahama National University, Faculty of Education and Human Sciences, Associate Professor, 教育人間科学部, 助教授 (50017927)

Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,800,000 (Direct Cost: ¥2,800,000)
KeywordsFatigue Crack Propagation / Stress Intensity Factor / Crack Propagation Rate / Method of Fatigue Test
Research Abstract

This research project was conducted from April 1997 to March 1999 with financial support from the Japanese Ministry of Education, Science & Culture (Grant-in-Aid for Scientific Research C-2). As can be readily seen nowadays, structural systems tend to increase in size and complexity, and naturally measures to guarantee or improve safety became essential. As a response to the new safety requirements, inspection, continuous monitoring and recording of the stress levels in structural members are not uncommon now. An important concept now is of that of "health monitoring"of structures in that defects and structural anomalies are timely detected as soon as they emerge. The objectives of this work were multi-faceted. The research started by a survey of the fracture mechanics models for fatigue crack propagation. Systems for monitoring any existing cracks and collecting pertinent data were to be analyzed. The estimation of crack propagation parameters based on methods of probabilistic reliabi … More lity engineering was also to be considered. A feasibility study of a new method using optic fibers and laser sensors for detection of cracks and measurement of strain deformation was to be conducted.
The main results and developments of the work are : 1) The efficacy of optical strain gages, based on the propagation of laser through optical fibers, developed specially for this research, was confirmed after comparisons with the classical ohmic strain gages ; 2) It was noticed that the determination of strains, which is done by analyzing light interference patterns, is difficult when the direction of movement (compression or tension) changes. It is now inquired if separating the laser light into a signal part and a reference one would not solve the problem ; 3) Testing for the assessment of the validity of the monitoring of propagation of fatigue cracks by laser sensors and optical fibers was conducted. Other conclusions were also drawn, but the problem of estimation of propagation parameters ins not mentioned in the report. In the continuation of this research, the clarification of the problem of determining the start point of crack propagation by using optical sensors is to be pursued.
Also, as an additional remark, this work as conducted accordingly to the initial research plan, and was concluded on March 1999. Less

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (3 results)

All Other

All Publications (3 results)

  • [Publications] 石塚鐵夫、竹村真孝: "光ファイバ・センサによる歪とき裂の検知"日本造船学会論文集. 第183号. 399-405 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Tetsuo Ishizuka, Masataka Takemura: "Strain Measureement and Crack Detection by Optical Fiber Sensors"Journal of The Society of Naval Architects of Japan. Vol. 183. 399-405 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] 石塚鐵夫、竹村真孝: "光ファイバ・センサによる歪とき裂の検知" 日本造船学会論文集. 第183号. 399-405 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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