球状黒鉛鋳鉄の二段二重重複応力下における疲労強度 : 回転曲げおよびねじり疲労

概要

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Rotating bending and torsional fatigue tests were carried out on the specimens of spheroidal graphite cast iron under constant amplitude loading or two-step loading. The initiation and propagation behaviors of microcracks were investigated through the successive observations by the plastic replica method and the observations of the fracture surface by a SEM. The obtained results show that the fatigue lives of the specimens under both types of loading are determined mainly by the propagation lives of small cracks. The ratio of fatigue limit τ_w/σ_w, is 0.79. The crack which is related to final fracture appears at a microshrinkage cavity. Miner's rule based on the fatigue life holds in rotating bending fatigue but does not necessarily hold in torsional fatigue.
一般社団法人日本機械学会の論文
1994-10-25