過小応力下の微視的き裂に及ぼす過大応力の影響 : フェライト系球状黒鉛鋳鉄のねじり疲労

概要

論文の詳細を見る
Torsional fatigue tests of ferritic spheroidal graphite cast iron were carried out and the fatigue processes were investigated through successive observations using the plastic replica method. The effects of overstress on the behavior of microcracks when a few cycles of overstress are applied intermittently (every 10^7 cycles) during the repetitions of understress to the specimen were discussed. The main results obtained are as follows : (1) The fatigue limit is determined by the limiting condition for the propagation of a Mode I microcrack. (2) When a few cycles of overstress are applied intermittently (every 10^7 cycles) during the repetitions of understress, the specimens can be broken even when the accumulated cycle ratio Σ(n/N) is much smaller than 1. (3) The effect of overstress on the fatigue behavior during understress cycling is larger in ferritic spheroidal graphite cast iron than in plain carbon steel.
一般社団法人日本機械学会の論文
1993-05-25