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Quantitative Evaluation of Multiple Cracking Damage by Means of Direct Current Potential Difference Method with Multiple-Type Probe

Research Project

Project/Area Number 12650086
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Materials/Mechanics of materials
Research InstitutionOKAYAMA UNIVERSITY

Principal Investigator

TADA Naoya  Okayama University, Faculty of Engineenng, Associate Professor, 工学部, 助教授 (70243053)

Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2000: ¥3,100,000 (Direct Cost: ¥3,100,000)
KeywordsMultiple-type probe / DC potential difference method / Multiple cracks / Fatigue
Research Abstract

The objective of the present research is to establish a method of quantitative evaluation of crack distribution from two-dimensional distribution of potential difference which can be measured by means of multiple-type probe. The multiple-type probe is composed of a lot of probes which are aligned in two rectangular directions. Although a conventional method, where only a pair of probes are used for measuring potential difference, has been applied to multiple cracking damage, it was impossible to determine whether relatively small number of large cracks exist or relatively large number of small cracks exist. In this study, electric field analysis and experiment were carried out and the following results were obtained.
1. The distribution of potential difference between two adjacent probes in multiple-type probe was calculated for known distribution of cracks and the relationship between the distribution of potential difference and that of cracks was formulated.
2. Using the formula, a method of quantitative evaluation of areal density (i. e. , the number of cracks in unit area) and mean length of cracks from mean and standard deviation of potential difference was proposed. The validity of the method was assured by numerical experiment.
3. A new evaluation method of the distribution of microscopic strain on the surface of specimen was proposed. In this method, micro-grid at intervals of about 10μm was described in advance on the surface of specimen using roughness tester, and a change in the shape of each grid was measured to evaluate the strain. This method was applied to small fatigued plate specimens of pure copper. Strain showed a relatively large scatter in microscopic scale and this seemed to be caused by microstructural inhomogeneity such as the difference in crystallographic orientations among neighboring grains. It was thought that the non-uniform strain of grains brought about crack initiation on the surface of specimen.

Report

(3 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] 多田直哉: "多端子型直流電位差法によるき裂分布の非破壊評価"日本機械学会材料力学部門講演会講演論文集. No.00-19. 317-318 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 多田直哉: "多数分布き裂型高温疲労損傷の直流電位差法による非破壊定量評価"日本材料学会第38回高温強度シンポジウム前刷集. 63-66 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 多田直哉: "多端子型直流電位差法による半楕円表面き裂の寸法と位置の推定"日本材料学会第39回高温強度シンポジウム前刷集. 160-164 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 多田直哉: "微小平板試験片を用いた純銅の繰り返し引張り"日本機械学会中国四国支部 第40期総会・講演会講演論文集. No.025-1. 47-48 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 多田直哉: "多端子型直流電位差法による半楕円表面き裂の非破壊評価"日本機械学会中国四国支部 第40期総会・講演会講演論文集. No.025-1. 49-50 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Naoya Tada: "Non-Destructive Evaluation of Distribution of Cracks by Means of DC-EPM with Multiple-Type Probe"Proceedings of the 2000 Annual Meeting of JSME/MMD. No. 00-19. 317-318 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Naoya Tada: "Quantitative Evaluation of Multiple Cracking Damage under High-Temperature Fatigue Conditions by Direct Current Electrical Potential Method"Proceedings of the 38th Symposium on Strength of Materials at High Temperatures. 63-66 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Naoya Tada: "Evaluation of Size, Shape and Location of a Semi-Elliptical Surface Crack by Direct Current Electrical Potential Method with Multiple-Type Probe"Proceedings of the 39th Symposium on Strength of Materials at High Temperatures. 160-164 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Naoya Tada: "Cyclic Tension of Pure Copper Using Small Plate Specimen"Proceedings of the 40th Annual Conference of Ghugoku-Shikoku Branch of JSME. No. 025-1. 47-48 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] Naoya Tada: "Non-Destructive Evaluation of a Semi-Elliptical Surface Crack by DC-EPM with Multiple-Type Probe"Proceedings of the 40th Annual Conference of Chugoku-Shikoku Rranch of JSME. N0. 025-1. 49-50 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 多田直哉: "多端子型直流電位差法による半楕円表面き裂の寸法と位置の推定"日本材料学会 第39回高温強度シンポジウム前刷集. 160-164 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 多田直哉: "微小平板試験片を用いた純銅の繰り返し引張り"日本機械学会中国四国支部 第40期総会・講演会講演論文集. No.025-1. 47-48 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] 多田直哉: "多端子型直流電位差法による半楕円表面き裂の非破壊評価"日本機械学会中国四国支部 第40期総会・講演会講演論文集. No.025-1. 49-50 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] 多田直哉: "多端子型直流電位差法によるき裂分布の非破壊評価"日本機械学会 材料力学部門講演会講演論文集. No.00-19. 317-318 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] 多田直哉: "多数分布き裂型高温疲労損傷の直流電位差法による非破壊定量評価"日本材料学会 第38回高温強度シンポジウム前刷集. 63-66 (2000)

    • Related Report
      2000 Annual Research Report

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Published: 2000-04-01   Modified: 2016-04-21  

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