二次元局所Hurst数を使用した金属破断面特性化手法(S14-2 切欠き効果と圧縮疲労強度特性,S14 金属材料の疲労特性と破壊機構)

概要

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Fractal analysis has been widely used to characterize the fracture surface. It has been recognized that the local Hurst exponent, which is based on the concept of self-affine fractal, is useful to detect the transition point of fracture surface. For the calculation of the local Hurst exponent, a high resolution profile is needed. To measure the profile, however, much time and effort are needed. Therefore, it is difficult to calculate all profiles of fracture surface and evaluate the feature of fracture surface in detail. In this study, a new method to calculate the two-dimensional local Hurst exponent is proposed. It is realized to evaluate the feature of fracture surface by using the local Hurst exponent. To investigate the validity of the two-dimensional local Hurst exponent, the calculation was applied to the gray-scaled images in which the stretched zone was observed and the width of stretched zone(SZW_c) was measured. Consequently, SZW_c calculated by the two-dimensional local Hurst exponent and detected by the human observation have the good agreement. Therefore, it was found that the two-dimensional local Hurst exponent is useful to detect the transition point of fracture surface.
社団法人日本機械学会の論文
2004-09-04