表面微小欠陥から発生する疲労き裂の進展に関する統計的研究

概要

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Rotating bending fatigue tests were carried out on SUS 304 stainless steel specimens with a number of corrosion pits on their surfaces to investigate statistically the propagation behaviors of surface cracks prior to their mutual coalescence. The important findings in the present study are summarized as follows. It was observed that the fatigue cracks were initiated from the pits having the diameters of more than about 50 μm among a number of pits whose diameters were distributed from a few micrometer to about 0. 1 mm. It was also found that the crack growth rate dl/dN was distributed inside a band of certain width on a log-log paper when plotted against σ√<πl>, and a regression line was drawn as a representative relation between dl/dN and σ√<πl>. By combining this relation with the experimentally four.d distribution of N_0, that is the number of cycles until crack grows to a length of l_0, the distributions of the crack length at a given cycle ratio and of the number of cycles at a given crack length were theoretically derived. The results were in good agreement with the experimental trends.
社団法人日本材料学会の論文
1981-05-15