Transactions of the Korean Society of Automotive Engineers (한국자동차공학회논문집)

The Korean Society of Automotive Engineers (한국자동차공학회)
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Determination and Applications of U and K$_{op}$ for Crack Closure Evaluation under Mixed-mode loading

혼합모드 하중 하에서 균열닫힘 평가에 대한 K$_{op}$와 U의 결정과 적용

  • Song Samhong (Department of Mechanical Engineering, Korea University) ;
  • Seo Kijeong (Department of Mechanical Engineering, Graduate School, Korea University) ;
  • Lee Jeongmoo (Research Institute of Engineering & Technolgy, Korea University)
  • 송삼홍 (고려대학교 기계공학과) ;
  • 서기정 (고려대학교 대학원 기계공학과) ;
  • 이정무 (고려대학교 공학기술연구소)
  • Published : 2005.05.01
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Abstract

Crack tip displacement is originated by tensile stress component, s and shear stress component, t on pure Mode I and pure Mode II. The crack tip displacement(CTD) depends on combined types of different two stress components under mixed-mode loading conditions (MMLC). Thus, the analysis of crack tip displacement must be CTD vector, dv which is composition of ds and dt under MMLC. In this paper, various effects of MMLC on the crack closure are studied experimentally. The crack closure magnitude is calculated from the information of crack tip displacement under MMLC. This information has been obtained from the high resolution optical microscope in direct observations of crack displacement behavior at the crack tip. Observed crack tip displacement is analyzed by using CTD vector to determine crack opening load. The various effects of MMLC on the crack closure are explained using crack opening ratio with crack length and mode mixture. The effective stress intensity factor considering crack closure is also discussed.

Keywords

References

  1. W. Elber, 'The Significance of Fatigue Crack Closure,' ASTM STP 486, pp.230-242, 1971
  2. S. Y. Kim and B. S. Lim, 'The Effect of Loading Waveform on the High Temperature Fatigue Crack Propagation in P92 and STS 316L Steel,' Transactions of KSAE, Vol.10, No.4, pp.136-140, 2002
  3. H. U. Staal and J. D. Elen, 'Crack Closure and Influence of Cycle Ratio R on Fatigue Crack Growth in Type 304 Stainless Steel at Room Temperature,' Engineering Fracture Mechanics, Vol.11, pp.275-283, 1979 https://doi.org/10.1016/0013-7944(79)90004-3
  4. J. J. Lee and W. N. Jr. Sharpe, 'Closure Measurements on Short Fatigue Cracks,' Mechanics of Fatigue Crack Closure, ASTM STP 982, pp.270-278, 1988
  5. C. Li, 'Vector CTD Criterion Applied to Mixed mode Fatigue Crack Growth,' Fatigue Fracture Eng. Mater. Struct., Vol.12, No.1, pp.59-65, 1989 https://doi.org/10.1111/j.1460-2695.1989.tb00508.x
  6. J. Tong, J. R. Yates and M. W. Brown, 'A Model for Sliding Mode Crack Closure. Part I: Theory for Pure Mode II Loading,' Engineering Fracture Mechanics, Vol.52, pp.599-611, 1995 https://doi.org/10.1016/0013-7944(95)00044-V
  7. J. Tong, J. R. Yates and M. W. Brown, 'A Model for Sliding Mode Crack Closure. Part II: Mixed Mode Loading and Applications,' Engineering Fracture Mechanics, Vol.52, pp.613-623, 1995 https://doi.org/10.1016/0013-7944(95)00045-W
  8. H. A. Richard and K. Benitz, 'A Loading Device for the Criterion of Mixed Mode in Fracture Mechanics,' Int. J. of Fracture, Vol.22, pp.R55-R58, 1983 https://doi.org/10.1007/BF00942726
  9. ASTM E647, 'Standard Test Method for Measurement of Fatigue Crack Growth Rates,' Annual Book of ASTM Standards, Vol.03.01, pp.565-601, 1995
  10. H. A. Richard, 'Some Theoretical and Experimental Aspects of Mixed Mode Fracture,' Advances Fracture Research, Vol.5, pp.3337-3344, 1986
  11. K. Tanaka, 'Fatigue Crack Propagation from a Crack Inclined to the Cyclic Tensile Axis,' Engineering Fracture Mechanics, Vol.6, pp.493-507, 1974 https://doi.org/10.1016/0013-7944(74)90007-1
  12. J. K. Sheth and W. W. Gerberich, 'The Effect of Test Frequency and Geometric Asperities on Crack Closure Mechanisms,' ASTM STP 982, pp.112-120, 1988
  13. D. C. Daile, 'The Crack Tip Displacement Vector Approach to Mixed-Mode Fracture,' Mixed-Mode Crack Behavior, ASTM STP 1359, pp.21-41, 1999
  14. L. W. WEI and M. N. JMES, 'Fatigue Crack Closure for Inclined and Kinked Cracks,' Int. J. of Fracture, Vol.116, pp.25-50, 2002 https://doi.org/10.1023/A:1020189817060
  15. S. H. Song and J. M. Lee, 'A Study on Fatigue Behavior at Pre-crack Tip under Mixed-mode Single Overloading (In the case of using the C-scan method),' Key Engineering Materials, Vol.270-273, pp.1171-1176, 2004 https://doi.org/10.4028/www.scientific.net/KEM.270-273.1171
  16. T. Nicholas, A. N. Palazotto and E. Bednarz, 'An Analytical Investigation of Plasticity Closure Involving Short Cracks,' ASTM STP 982, pp.361-379, 1988
  17. D. H. Chen and H. Nisitani, 'Analytical and Experimental Study of Crack Closure Behavior Based on an S-Shaped Unloading Curve,' ASTM STP 982, pp.475-488, 1988