A Chord Vibration Method in Measuring the Deformation of Member Bodies

Research Project

Project/Area Number	61850114
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	資源開発工学
Research Institution	Kyoto University
Principal Investigator	FUJINAKA Yuzo Prof., Kyoto Univ., 工学部, 教授 (50025855)
Co-Investigator(Kenkyū-buntansha)	杉井謙一株式会社神戸製鋼所, エンジニアリング事業部, 係長早崎清志神鋼鋼線工業株式会社, 研究開発部, 研究員 TSUKADA Kazuhiko Instructor, Kyoto Univ. (, 工学部, 助手 (10179971) HANASAKI Koichi Assoc. Prof., Kyoto Univ. (, 工学部, 助教授 (20026123) HAYASAKI Kiyoshi Researcher, Shinko Wire Co., Ltd. SUGII Ken-ichi Chief Researcher, Kobe Steel, ltd.
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,900,000 (Direct Cost: ¥2,900,000) Fiscal Year 1987: ¥1,200,000 (Direct Cost: ¥1,200,000) Fiscal Year 1986: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywords	Stress measurement / Long term stress measurement / Strain measurement / Chord vibration / Open pit mining machinery / 応力測定 / 弦振動法 / 非破壊検査 / 静ひずみ測定
Research Abstract	A couple of fine metal chords are stretched across the two bridge pieces which have been fixed onto the member body where the deformation or the stress is to be measured. Frequency of fundamental vibration of the chord is obviously related to the tension, span and linear density, so that the change of span of the chord, that is the deformation of member body, can be translated from the frequency number at any time. An electric current is fed into the chord, and it results in a continual vibration with the aid of an opto- electronic position sensor, together with a phase shifting circuitry. The creep of the chord under such the tight stretch for long term, will be one of the problem to be considered in the future. Corrosion of the chord exposed in open air should also be considered.