International Journal of Precision Engineering and Manufacturing

  • 제3권3호
  • /
  • Pages.76-81
  • /
  • 2002
  • /
  • 2234-7593(pISSN)
  • /
  • 2005-4602(eISSN)
한국정밀공학회 (Korean Society for Precision Engineering)
권호 표지

Fatigue Crack Retardation and Retardation Mechanism in Variable Loading (The Effects of Crack Tip Branching in Crack Growth Retardation)

  • 발행 : 2002.07.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

In order to study the fatigue crack and retardation mechanism in variable loading, the effects of crack tip branching in crack growth retardation were examined. The characteristics of crack tip branching behavior were considered with respect to microstructure and crack tip branching angle was examined. Crack tip branching was observed along the grain boundary of finite and pearlite structure. It was found that the branching angle ranges from 25 to 53 degrees. Using the finite element method, the variable of crack driving farce to branching angle was examined. The effective crack driving farce (K$\_$eff/) decreased as the branching angle increased. The rate of decrease was 33% for kinked type and 29% for forked one. It was confirmed that the effect of crack tip branching is a very important factor in crack growth retardation. Therefore, crack branching effect should be considered in building the hypothetical model to predict crack growth retardation.

키워드

참고문헌

  1. Fleck, N. A., Influence of stress state on crack growth retardation ASTM STP 924, pp. 157-183, 1988
  2. S. Suresh, Micromechanism of fatigue crack growth retardation following overloads Eng. Fract. Mech. Vol. 18, No. 3, pp. 577-593, 1983 https://doi.org/10.1016/0013-7944(83)90051-6
  3. Tomas, W. M., The effect of single overload upon fatigue crack in 5083-H321 Al Eng. Fract.Mech., Vol. 23,pp. 1015-1029, 1986 https://doi.org/10.1016/0013-7944(86)90145-1
  4. Fleck, N. A., Fatigue carck growth due to periodic underloads and periodic overloads, Acta Metallurgica, Vo1.33,pp. 1339-1354, 1985 https://doi.org/10.1016/0001-6160(85)90244-5
  5. Vardar, O., Effects of single overload in FCP , Eng. Fract. Mech., Vol. 30, pp. 329-335, 1988 https://doi.org/10.1016/0013-7944(88)90191-9
  6. Chanani, G.R., Observation of crack closure behavior after single overload cycle in 7075-T6 single notched specimens, Eng. Fract.Mech, Vol. 9, pp.65-73, 1977 https://doi.org/10.1016/0013-7944(77)90052-2
  7. Ward-Close, C. M. and Ritche, R. O, On the role of crack closure mechanism in influencing fatigue crack growth following tensile overload in a Ti alloy, ASTM STP 982, pp. 93-111, 1988
  8. Alawi, H., Fatigue carck growth prediction under random peaks and sequence loading, J Eng .Tech. 111, pp. 339,1989
  9. Robin, C. Jnfluence of an overload on the fatigue crack growth in steels, Fat. of Eng. Mat. And Struct.,Vol. 6, No.1, pp. 1-13, 1983 https://doi.org/10.1111/j.1460-2695.1983.tb01135.x
  10. de Castro, J. T. P., Decrease in crack closure and delay of fatigue crack growth in plane strain, Scripta Metallurgica, Vol. 16, pp. 1443-1446, 1982 https://doi.org/10.1016/0036-9748(82)90443-4
  11. S. H. Song, and Y. K. Kwon, 'A Study on Crack Growth Retardation Behavior by Single Overload.' Journal of KSME, Vol. 19, pp. 451-162, 1995
  12. Suresh, S., Crack Deflection : Implication for the growth of long and short fatigue cracks, Metallurgical Transactions A, Vol. 14A, pp. 2375-2385, 1983 https://doi.org/10.1007/BF02663313
  13. Wilenborg, J., A crack growth retardation model using an effective stress concept, Technical Memorandum 71-1-FBR, Air Force Flight Dynamic Lab, Wright Patterson Air Fo