Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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An Experimental Method for Measuring Q

Q의 실험적 측정법

  • 김동학 (전남대학교 대학원 기계공학과) ;
  • 이정현 (전남대학교 대학원 기계공학과) ;
  • 강기주 (전남대학교 기계시스템공학부)
  • Published : 2003.09.01
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Abstract

An experimental method to measure Q-parameter in-situ is described. The basic idea comes from the fact that the side necking near a crack tip indicates the loss of stress triaxiality, which can be scaled by Q. From the out-of-plane displacement and the in-plane strain near the surface of side necking, stress field averaged through the thickness is calculated and then Q is determined from the difference between the stress field and the HRR field corresponding to the identical J-integral. To prove the validity, three-dimensional finite element analysis has been performed for a CT configuration with side-groove. Q-value which was calculated directly from the near-tip stress field is compared with that determined by simulating the experimental procedure according to the proposed method, that is, the Q-value determined from the lateral displacement and the in-plane strain. In addition, the effect of location where the displacement and strain are measured is explored.

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References

  1. Chao, Y. J. and Lam, P. S., 1998, 'On the Use of Constraint Parameter $A_2$ Determined from $\delta_5$ Technique in Predicting Fracture Event,' Fatigue, Fracture, and Residual Stress ASME, pp. 197-205
  2. Kim, H.J. Kim, D.H., Yang, K.J. and Kang K.J., 2003, 'Variation of A2 with Crack Propagation in a Ductile Metal; Experimental Evaluation,' Transaction of the KSME, Vol. 27, pp. 119-125 https://doi.org/10.3795/KSME-A.2003.27.1.119
  3. Yuan H. and Broacks, W., 1998, 'Quantification of Constraint Effects in Elastic-Plastic Crack Front Fields,' Journal of the Mechanics and Physics of Solids, Vol. 46, pp. 219-241 https://doi.org/10.1016/S0022-5096(97)00068-9
  4. Heerens, J., Hellmann, D. and Zerbst, U., 1996, 'Probendicken- und Ligamenteinschnurung, zwei Grossen zur Erfassung der Constrintabhangigkeit won R-Kurven,' Prodceedings for 28. Vortragsveranstaltung, des DVM-Arbeitskrieses Bruchvorgange, ed. W. Brocks, pp.389-400. Deutcher Verband fur Material Prufung, Feb. 1996 in Bermen
  5. Pardoen, T., Marchal, Y and Delannay, F., 1999, 'Thickness Dependence of Cracking Resistance in Thin Aluminium Plates,' Journal of the Mechanics and Physics of Solids. Vol. 47, pp. 2093-2123 https://doi.org/10.1016/S0022-5096(99)00011-3
  6. O'Dowd, N.P. and Shih, C.F., 1991, 'Family of Crack-Tip Fields Characterized by a Triaxiality Parameter- I. Structure of Field,' Journal of the Mechanics and Physics of Solids, Vol. 39, pp. 989-1015 https://doi.org/10.1016/0022-5096(91)90049-T
  7. O'Dowd, N.P. and Shih, C.F., 1992, 'Family of Crack-Tip Fields Characterized by a Triaxiality Parameter- II. Fracture Application,' Journal of the Mechanics and Physics of Solids, Vol. 40, pp. 939-963 https://doi.org/10.1016/0022-5096(92)90057-9
  8. Kang, Ki-Ju, Kim, Si-Young, Kim, Heon-Joong and Jeung Dae-Yeul, 2003, 'Effect of Loading Rate Upon Fracture Behavior of Ferritic Steel Under Large Scaled Yielding,' Nuclear Engineering and Design, Vol. 219, pp. 11-18 https://doi.org/10.1016/S0029-5493(02)00288-1
  9. Earmme, Y.Y. and Lee, Y.B., 1996, 'Study of Effect of Dynamic Strain Aging on Fracture Toughness for Main Stream Line Piping of Nuclear Power Plant,' Korea Electric Power Corporation
  10. Lee, Jeong-Hyun, Jeon, Moon-Chang and Kang, Ki-Ju, 2003, 'Evaluation of Displacement Measurement Technique Using Laser Speckle and Digital Image Correlation Method,' Journal of the Korean Society of Precision Engineering, Vol. 20, pp. 47-54
  11. Kim, Dong-Hak, Lee, Jeong-Hyun and Kang, Ki-Ju, 2003, 'The Application of the Experimental Method of Measuring Q to Ductile Material,' in preparation