• Title/Summary/Keyword: 최소 변형률 에너지 밀도 이론

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Application of the Static Photoelastic Experimental Hybrid Method to the Crack Propagation Criterion for Isotropic Materials (등방성체의 균열전파 기준에 정적 광탄성 실험 하이브리드 법 적용)

  • Shin Dong-Chul;Hawong Jai-Sug;Nam Sung-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.8 s.227
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    • pp.1229-1236
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    • 2004
  • The specimen materials used in this research are isotropic epoxy resins. The static photoelastic experiment was applied to them. And then the specimens used in photoelastic experiment were fractured under static load. The static photoelastic experimental hybrid method was introduced and its validity had been assured. Crack propagation criterion used the stress components, which are considered the higher order terms, obtained from the static photoelastic experimental hybrid method was introduced and it was applied to the minimum strain energy density criterion, the maximum tangential stress criterion and mode mixity. Comparing the actual initial angle of crack propagation with the theoretical initial angle of crack propagation obtained from the above failure criterions, the validities of the above two criterions are assured and the optimal distance (r) from the crack-tip is 0.01mm in order to get the initial angle of crack propagation of isotropic epoxy resin.

A Study on the Interfacial Crack Propagation Criterion for Two Dissimilar Isotropic Bimaterial by the Static Photoelastic Experimental Hybrid Method (정적 광탄성 실험 하이브리드 법에 의한 두 상이한 등방성 이종재료의 계면균열전파 기준에 관한 연구)

  • Tche, Konstantin;Hawong, Jai-Sug;Shin, Dong-Chul;Nam, Sung-Su;Nam, Jeong-Hwan
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1216-1221
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    • 2003
  • The specimen materials used in this research is bimaterial. The static photoelastic experiment was applied to them. And then the specimens used in photoelastic experiment were fractured under static load. The static photoelastic hybrid method was introduced and it's validity had been assured. The static photoelastic hybrid method was applied to the Minimum Strain Energy Density Criterion, the Maximum Tangential Stress Criterion and Mode Mixity. Crack propagation criterion by the static photoelastic hybrid method was introduced and it was applied to the above various failure theories. Comparing the experimental initial angle of crack propagation with the theoretical initial angle of crack propagation from the various failure criterions. And then the optimal crack propagation criterion was suggested and it's validity was assured.

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Fatigue Crack Growth Rates and Directions in STS304 under Mode I and Mixed Mode (단일 및 혼합모드하에서 304스테인리스강의 피로균열 진전속도와 방향특성)

  • 권종완;양현태
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.3
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    • pp.102-109
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    • 2002
  • The fatigue crack growth under mixed mode condition has been discussed within the scope of linear fracture mechanics such as maximum tangential stress, maximum tangential principal stress and minimum strain energy density. The purpose of this study is to investigate the characteristics of fatigue test crack growth in 304 stainless steel under mixed node. The fatigue test results carried out by using inclined pre-crack specimens was compared to both of the theoretical predictions of the criteria, maximum tangential stress and stain energy density. As difference from theoretical analysis, the transition region from mixed mode to mode I appeared in the fatigue test. There is deep relationship between the angle of slanted pre-crack and transition. Therefore, as applying the different stress intensity factor to each node I+II and mode I, the directions and rates of fatigue crack growth are evaluated more accurately under mixed mode.

A Study on the Crack Propagation Criterion of Orthotropic Material by the Static Photoelastic Experimental Hybrid Method (정적 광탄성 실험 하이브리드법에 의한 직교이방성체의 균열전파 기준에 관한 연구)

  • Shin, Dong-Chul;Hawong, Jai-Sug;Nam, Sung-Su;Kwon, O-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1799-1806
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    • 2004
  • The static photoelastic experiment was applied to orthotropic materials. And then the specimens used in photoelastic experiment were fractured under static load. The static photoelastic experimental hybrid method for orthotropic material was introduced and its validity had been assured. Crack propagation criterion used the stress components, which are considered the higher order terms, obtained from the static photoelastic experimental hybrid method was introduced and it was applied to the minimum strain energy density criterion, the maximum tangential stress criterion and mode mixity. Comparing the actual initial angle of crack propagation with the theoretical initial angle of crack propagation obtained from the above failure criterions, the validities of the above two criterions are assured and the optimal distance (${\gamma}$) from the crack-tip is 0.01mm in order to get the initial angle of crack propagation of orthotropic material(C.F.E.C.).