일정 응력확대계수 제어하의 피로균열전파수명 분포의 파라메터 특성에 관하여

Characteristics of Parameters for the Distribution of Fatigue Crack Growth Lives under Constant Stress Intensity Factor Control

  • 김선진 (부경대학교 기계공학부) ;
  • 김영식 (부경대학교 기계공학부) ;
  • 정현철 (부경대학교 기계공학과 대학원)
  • Kim, Seon-Jin (School of Mechanical Engineering, Pukyong National University) ;
  • Kim, Young-Sik (School of Mechanical Engineering, Pukyong National University) ;
  • Jeong, Hyeon-Cheol (Graduate Student, Dept. of Mechanical Engineering, Pukyong National University)
  • 발행 : 2002.10.25

초록

The characteristics of parameters for the probability distribution of fatigue crack growth lives by the non-Gaussian random process simulation method is investigated. In this paper, the material resistance to fatigue crack growth is treated as a spatial random process, which varies randomly on the crack surface. Using the previous experimental data, the crack length - the number of cycles curves are simulated. The results are obtained for constant stress intensity factor range conditions with stress ratio of R=0.2, three specimen thickness of 6, 12 and 18mm, and the four stress intensity level. The probability distribution function of fatigue crack growth lives seems to follow the 3-parameter Wiubull and shows a slight dependence on specimen thickness and stress intensity level. The shape parameter, ${\alpha}$, does not show the dependency of thickness and stress intensity level, but the scale parameter, ${\beta}$, and location parameter, ${\upsilon}$, are decreased by increasing the specimen thickness and stress intensity level. The slope for the stress intensity level is larger than the specimen thickness.

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