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Damage Monitoring of Metal Materials by Laser Speckle

Research Project

Project/Area Number 02650080
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 材料力学
Research InstitutionChubu University

Principal Investigator

KATO Akira  Chubu University, Mechanical Eng., Associate Professor, 工学部, 助教授 (00113085)

Co-Investigator(Kenkyū-buntansha) KAGAYA Chuji  Chubu University, Mechanical Eng., Associate Professor, 工学部, 助教授 (90097668)
Project Period (FY) 1990
Project Status Completed (Fiscal Year 1990)
Budget Amount *help
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1990: ¥1,700,000 (Direct Cost: ¥1,700,000)
KeywordsNondestructive inspection / Damage assessment / Laser speckle / Image processing / Plastic strain / Surface roughness
Research Abstract

This study investigated a method to detect damage of metals with no contact using the laser speckle technique. This method is based on observation of the change of laser speckle pattern depending on the surface roughness and texture change of the material caused by plastic deformation after loading of materials. The laser speckle pattern was analyzed automatically and quantitatively using an image processing system in this experiment. The Image processing system used in this study is a personal computer based one and the resolution of the image memory is 512X512. The image of the laser speckle pattern was input into the image processing system using a CCD camera. Software to analyze the laser speckle pattern was developed on the personal computer using C language. It is important in this study to find a proper parameter which can express the features of the laser speckle pattern accurately. A new parameter, c_<kappa>, was derived to statistically express the feature of the speckle pattern. It was found from the experimental result that this parameter can express the features of speckle pattern accurately and has excellent reproducibility. Experiment was carried out for both static tensile and tensile fatigue loading using an aluminium alloy as the material. The result for static tensile test shows that there is a fixed relation between c_<kappa> and plastic strain epsilon_<rho> and the relation can be expressed with a simple equation. Therefore, it is possible to accurately estimate the magnitude of plastic strain by the c_<kappa> parameter based on the equation. The change of the c_<kappa> parameter was small for fatigue loading. However, when stress amplitude was rather large, the c_<kappa> parameter changed perceptively with the increase of the stress cycles. It may be concluded that there is a possibility of detecting fatigue damage by observing the change of the laser speckle pattern.

Report

(2 results)
  • 1990 Annual Research Report   Final Research Report Summary
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Akira Kato,Y.Z.Dai,F.P.Chiang: "Damage Monitoring of Aluminium by Laser Speckle" Proc.of 9th International Conference on Experimental Mechanics. 1940-1948 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Akira Kato,Y.Z.Dai,F.P.Chiang: "Damage Monitoring of Materials by Laser Speckle Assited by Image processing Technique(1st Report:Basic Experiment)" JSME International Journal. (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Akira Kato, Y. Z. Dai and F. P. Chiang: ""Damage Monitoring of Aluminium by Laser Speckle" Proc. 9th International Conference on Experimental Mechanics. 1940-1948 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Akira Kato, Y. Z. Dai and F. P. Chiang: ""Damage Monitoring of Metal Materials by Laser Speckle Assisted by Image Processing Technique (lst Report : Basic Experiment)" JSME International Journal. (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] Akira Kato,Y.Z.Dai,F.P.Chiang: "Damage Monitoring of Aluminium by Laser Speckle" Proc.of 9th International Conference on Experimental Mechanics. 1940-1948 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] Akira Kato,Y.Z.Dai,F.P.Chiang: "Damage Monitoring of Metal Materials by Laser Speckle Assisted by Image Processing Technique (1st Report:Basic Experiment)" JSME International Journal. (1991)

    • Related Report
      1990 Annual Research Report

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Published: 1990-04-01   Modified: 2016-04-21  

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