<論文>高温におけるクリープとクリープ・疲労相互作用下の表面き裂の伝ぱ

概要

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We have previously conducted crack propagation tests using macroscopic through thickness crack speci -mens under creep conditions, and found out nonlinear fracture mechanics behavior. Investigations on surface cracks are more practical than those on through thickness cracks, so that these will be important. In this study, experimental investigations on the propagations of large and small surface cracks of sus 304 stainless steel and 2 1/4Cr-1Mo steel were erformed under cree and creep-fatigue conditions in air. It was found that static creep crack propagation rates of the small surface crack of sus 304 and the large suface crack of Cr-Mo steel were roughly correlated with those of macroscopic through thickness cracks by modified J integral J. Under repeated load, the crack propagation rate of the large surface crack of sus 304 was correlated with the stress intensity range △K at low propagation rate, whereas it was correlated with J at high propagation rate and coincided with the rate of static creep crack. The crack propagation rate of the small surface crack of sus 304 was lower than of the large surface crack, and it was correlated with J. This would be because small scale yielding condition was not satisfied due to the small crack size.
宇部工業高等専門学校の論文
1983-03-23