• Title/Summary/Keyword: Crack Meacurement

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Small Fatigue Crack Measurement and Crack Growth Characteristics for Smooth and Notch Specimens (평활 및 노치재의 미소피로균열측정과 성장특성)

  • 이종형
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2145-2152
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    • 1993
  • The objective of this paper is to examine the detection limit, growth characteristics and notch curvature radius in short crack problem. Measurement techniques such as ultrasonic method and back-face strain compliance method were adopted. The fatigue crack growth rate of the short crack is slower than that of a long crack for a notched specimen. The characteristic of crack growth and crack closure is same as the case of a delay of crack growth caused by constant amplitude load for an ideal crack or single peak overload for a fatigue crack. The short crack is detected effectively by ultrasonic method. A short surface crack occurs in the middle of specimen thickness and is transient to a through crack depth is larger than the notch curvature radius.