透過回折波による亀裂先端位置測定法の測定精度 [in Japanese] The Accuracy of Crack Tip Position Measurement by using Diffracted P-wave [in Japanese]
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The author suggested a measurement method of crack tip position in a previous paper. This method utilizes the polarity of first motion of diffracted P-wave at a tip of a crack, and this has the advantage of independence from effect of frequency of P-wave. The polarity of first motion of diffracted P-wave is decided by the incidence and the diffraction angle at a tip of a crack. The relationship of these two angles is influenced by only Poisson's ratio. In order to measure a crack tip position with high accuracy, it is necessary to clear the effect of Poisson's ratio. In the present paper, relationship between the first motion polarity of diffracted P-wave and a crack tip position and a crack angle was studied, and the effect of Poisson's ratio on the relationship was mentioned. The main results obtained from this study are, 1) According to the increase of Poisson's ratio, displacement of a change point of first motion polarity of diffracted P-wave increases. 2) Regardless of the crack tip position and the crack angle, the smaller Poisson's ratio becomes, the less Poisson's ratio effects on displacement of a change point of first motion polarity. 3) According to the decrease of Poisson's ratio, error of the analysis increase. 4) Replacement of transmitters and receivers according to the crack tip position and the crack angle enables measurements with a high accuracy.
- Journal of MMIJ
Journal of MMIJ 115(6), 423-428, 1999-06
The Mining and Materials Processing Institute of Japan