• Title/Summary/Keyword: 유효 소성 역 개념

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A Fracture Mechanic's Study for Crack Growth Retardation Phenomenon using Effective Plastic Zone Concept (균열성장 지연현상에 대한 유효 소성역 개념을 사용한 파괴역학적 연구)

  • Kang, Yong-Goo;Lee, Tae-Won;Park, Chang-Yong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.2
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    • pp.112-120
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    • 2015
  • In this study, the growth rate of surface cracks (da/dN) during the retardation period was analyzed in terms of effective stress intensity factor range(${\Delta}K_{eff}^*$) obtained by using the proposed effective plastic zone concept. Effective stress intensity factors obtained by using the effective plastic zone concept were smaller than those obtained by using Willenborg analysis. On the growth rate of surface cracks analyzed by ${\Delta}K$, the dependence of overload stress levels appears. On the growth rate by ${\Delta}K_{eff}$ obtained by Willenborg analysis, there is a linear relationship with two different slops between da/dN and ${\Delta}K_{eff}$. However, on the growth rate by ${\Delta}K_{eff}^*$ obtained by the proposed effective plastic zone concept, there is a linear relationship between da/dN and ${\Delta}K_{eff}^*$ that coincides with the results of constant amplitude loading.

Study for Retardation Phenomenon (균열 성장 지연현상에 대한 연구)

  • Kang, Yong-Goo;Lee, Tae-Won;Kim, Dong-Myung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.5
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    • pp.42-49
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    • 2013
  • In this study, in order to analyze the crack retardation behaviors, effective plastic zone concept was proposed. By use of the proposed concept, crack retardation period, compressive residual stress and variation of effective plastic zone shapes were obtained. The results were compared with those of Willenborg model. Retardation period, compressive residual stress and effective plastic zone size obtained by using effective plastic zone concept were larger then the results obtained by using Willenborg analysis. Effective stress intensity factors obtained by using effective plastic zone concept were smaller then the results obtained by using Willenborg analysis.