機械構造用鋼の低サイクル疲労における表面き裂の進展特性とそれに基づく寿命の評価

概要

論文の詳細を見る
The smooth specimen of JIS S35C and SNCM 439 steels, which were heat-treated in several conditions, were low-cycle fatigued. Then, the growth rate of surface small crack, da/dN, was analyzed in terms of the cyclic J-integral range, ΔJ, and the strain intensity factor range, ΔK_ε. The crack growth rates plotted against ΔJ and ΔK_ε are approximately expressed by linear lines on a log-log diagram. The considerable scatter inherent in problems of a small crack, however, almost cover the small difference in the crack growth property among materials. As a result, the universal equations can be established for da/dN vs. ΔJ and da/dN vs. ΔK_ε relations, independently of kinds of materials used. The equations derived from combining the above two relations with the cyclic stress-strain curve describe well the fatigue life curve which bends downwards in the regime of the lower plastic strain range in materials of a high strength and low ductility as well as usual Coffin-Manson plots.
一般社団法人日本機械学会の論文
1985-03-25