工業用純チタンにおける疲労き裂の開閉口挙動 : 直流電位差法による測定

概要

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Fatigue crack growth characteristics in commercially pure titanium have been studied using SEN sheet specimens under push-pull loading with stress ratios ranging from -1 to 1/3. Crack closure has been investigated by monitoring the electric potential using a DC-potential drop method. A load level vs. electric potential curve showed a fairly sharp bend during increasing a load level within one load cycle. The load at this bend has been identified to the crack tip opening load by examining the crack profiles using a two-stage replica method. Crack closure was observed to occur at every stress ratios except at R=1/3. The exponent m for the crack growth relation da/dN=C (ΔK)^m was about 3 for the cracks longer than 1 mm. Crack growth rates for cracks shorter than about 1 mm and at R=-1 were fairly higher than those expected from the relation for longer cracks.
一般社団法人日本機械学会の論文
1985-02-25