OS1423 き裂成長予測による低サイクル疲労の損傷評価 : 繰返し熱応力下での疲労寿命

Abstract

The influence of crack growth on the fatigue life was investigated for a ramp change in the fluid temperature on the surface. The stress intensity factor was obtained by the weight function method considering the stress gradient in the thickness direction. The estimated fatigue life under the cyclic thermal loading could be 1.6 times longer than that under the uniform stress distribution. The critical size for the fatigue life determination was assumed to be 3 mm for fatigue test specimens of 10 mm diameter. By determining the critical size by structural integrity analyses, the fatigue life was increased under the cyclic thermal stress.