An experimental investigation into dynamic fracture: I. Crack initiation and arrest (original) (raw)

Abstract

Problems of dynamic crack propagation are examined experimentally in a series of four papers. In this paper, the first of this series, crack initiation and arrest are investigated in thin sheets of Homalite-100. It is found that as the rate of loading increases to as high as 105 MPa/sec, the stress intensity factor required to initiate crack growth increases markedly. Crack arrest resulting from a simulated pressurized semi-infinite crack in an unbounded medium was found to occur abruptly. There was no continuous deceleration and the crack always stopped at a constant value of the stress intensity factor, which value was lower than the stress intensity factor required for quasi-static crack growth initiation.

The second paper in this series deals with the occurrence of micro cracks at the front of the running main crack which control the rate of crack growth. The micro cracks are recorded by real time photography. By the same means it is shown that these micro cracks grow and turn away smoothly from the direction of the main crack in the process of branching.

The third contribution establishes the hitherto unreported occurrence that cracks can propagate rapidly with constant velocity even though the stress intensity factor varies considerably during this propagation. This velocity is determined by the initial stress wave loading on the crack tip, and is changed, within limits, only by stress pulses of sufficient magnitude and brevity of rise time.

The final paper in the series deals with the effect of stress waves on the behavior of running cracks, in particular with the influence of stress waves on the branching phenomenon. Also, crack curving under transient stress waves is examined.

These results are believed to apply to materials other than Homalite 100 and the reasons for this belief are discussed in this first contribution.

Résumé

On passe en revue sous l'angle expérimental dans quatre articles les problèmes de propagation dynamique d'une fissure. Dans ce premier mémoire, on étudie l'amorçage et l'arrêt d'une fissure dans des feuillards d'Homalite 100. On trouve que lorsque la vitesse de sollicitation croit jusque 105 MPa/sec, le facteur d'intensité de contrainte nécessaire au démarrage de la propagation de la fissure s'accroît de manière notable. L'arrêt de fissuration caractérisant une fissure semi-infinie supposée soumise à une pression dans un milieu non limité se produit brutalement. On n'observe pas de décélération continue et la fissure s'arrête pour une valeur constante du facteur d'intensité de contraintes, laquelle est inférieure à celle nécessaire à l'amorçage d'une croissance de fissure semi-statique.

Le deuxième mémoire de cette série traite de l'apparition de microfissures sur le front de propagation de la fissure principale, et de leur rôle dans la vitesse de croissance d'une fissure. Les microfissures sont enregistrées par photographie en temps réel. On montre par la même méthode comment les microfissures croissent et s'écartent de la direction de propagation principale, dans un processus d'arborescence.

La troisième contribution fait état d'un phénomène jusqu'ici non décrit, selon lequel des fissures peuvent se propager rapidement à une vitesse constante, même si le facteur d'intensité de contraintes varie de manière significative au cours de cette propagation.

On détermine cette vitesse constante à partir de l'onde de choc initiale associée à la sollicitation de l'extrémité de l'entaille et one montre qu'elle ne peut être modifiée, dans certaines limites, que par des impulsions d'une amplitude et d'une accélération suffisante.

Le dernier article de la série est relatif à l'effet des ondes de contraintes sur le comportement de fissures en cours de développement, et, en particulier à leur influence sur le phénomène d'arborescence. On examine également comment des fissures peuvent s'infléchir sous l'effet d'ondes de contraintes.

Les auteurs pensent que ces résultats sont applicables à d'autres matériaux que l'Homalite 100. Les raisons de cette assertion sont discutées dans la présente contribution.

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References

  1. A.A. Griffith,Philosophical Transactions of the Royal Society of London: Series A, 221 (1920) 163–198.
    Google Scholar
  2. A.A. Griffith,Proceedings of the First International Congress of Applied Mechanics (1924) 55–63.
  3. G.R. Irwin,Handbuch der Physik, VI, ed. Flügge (1958) 558–590.
  4. G.C. Smith, Ph.D. thesis, California Institute of Technology (1975).
  5. J.F. Kalthoff et al., in_Fast Fracture and Crack Arrest, ASTM STP 627_ (1977) 161–176.
  6. H. Schardin, in_Fracture_, ed. Averbach et al., John Wiley (1959) 297–330.
  7. L.B. Fréund,Journal of Elasticity 2 (1972) 341–349.
    Google Scholar
  8. G.R. Irwin et. al.,Experimental Mechanics 19 (1979) 121–128.
    Google Scholar
  9. A.S. Kobayashi and S. Mall,Experimental Mechanics 18 (1978) 11–18.
    Google Scholar
  10. T. Kobayashi and J.W. Dally, in_Fast Fracture and Crack Arrest_, G.T. Hahn and M.F. Kanninen, eds., ASTM STP 627 (1977) 257–273.
  11. J. Field,Contemporary Physics 12 (1971) 1–31.
    Google Scholar
  12. W.M. Beebe, Ph.D. Thesis, California Institute of Technology (1966).
  13. V.M. Finkel et al.,Physics of Metals and Metallurgy 15 (1963) 754–764.
    Google Scholar
  14. K. Ravi-Chandar and W.G. Knauss, GALCIT SM 82-9 Report, October 1982, California Institute of Technology, Pasadena, Ca (to appear in_International Journal of Fracture_).
  15. K. Ravi-Chandar and W.G. Knauss, GALCIT SM 83-9 Report, March 1982, California Institute of Technology, Pasadena, Ca (to appear in_International Journal of Fracture_).
  16. K. Ravi-Chandar and W.G. Knauss, GALCIT SM 84-6 Report, April 1982, California Institute of Technology, Pasadena, Ca (to appear in_International Journal of Fracture_).
  17. D.A. Shockey, J.D. Kalthoff and D.C. Erlich,International Journal of Fracture 22 (1983) 217–229.
    Google Scholar
  18. H. Homma, D.A. Shockey, and Y. Murayama,Journal of Mechanics and Physics of Solids 31 (1983) 261–279.
    Google Scholar
  19. J.W. Dally,Experimental Mechanics 19 (1979) 349–361.
    Google Scholar
  20. J.F. Kalthoff, in_Proceedings: Workshop on Dynamic Fractur_, Knauss, Ravi-Chandar, and Rosakis, eds. California Institute of Technology, Pasadena, CA (February 1983.).
    Google Scholar
  21. T.L. Paxson and R.A. Lucas, in_Dynamic Crack Propagation_, G.C. Sib, ed., Noordhoff International (1972).
  22. T. Kanazawa, S. Machida, T. Teramoto and H. Yoshinari,Experimental Mechanics 21 (1981) 78–88.
    Google Scholar
  23. D.A. Shockey, J.F. Kalthoff, W. Klemm, and S. Winkler,Experimental Mechanics 23 (1983) 140–145.
    Google Scholar
  24. P. Manogg,International Journal of Fracture 2 (1966) 613.
    Google Scholar
  25. H.P. Rossmanith, and W.L. Fourney,Experimental Mechanics 22 (1982) 111–116.
    Google Scholar
  26. W. Goldsmith and F. Katsamanis,Experimental Mechanics 19 (1979) 235–244.
    Google Scholar
  27. K. Ravi-Chandar and W.G. Knauss,International Journal of Fracture 20 (1982) 209–222.
    Google Scholar
  28. J.W. Dally and A. Shukla,Mechanics Research Communications 6 (1979) 236–244.
    Google Scholar
  29. L.B. Freund, in_Proceedings: Workshop on Dynamic Fracture_, Knauss, Ravi-Chandar, and Rosakis, eds., California Institute of Technology, Pasadena, CA (February 1983).
    Google Scholar
  30. W.B. Bradley, Ph.D. thesis, University of Washington (1969).
  31. I. Emri and W.G. Knauss,Computers and Structures 13 (1981) 123–128.
    Google Scholar
  32. S.N. Zhurkov and V.S. Kukshenko,International Journal of Fracture 11 (1975) 629–639.
    Google Scholar
  33. D.R. Curran et al.,Journal of Applied Physics 44 (1973) 4025–4038.
    Google Scholar
  34. R.C. Hoagland et al.,Metallurgical Transactions 3 (1972) 123–136.
    Google Scholar
  35. M.F. Kanninen,International Journal of Fracture 10 (1974) 415–430.
    Google Scholar
  36. L.B. Freund,Journal of Mechanics and Physics of Solids 25 (1977) 69–79.
    Google Scholar
  37. P.B. Crosley and E.J. Ripling,Fast Fracture and Crack Arrest, ASTM ASTP 627 (1977) 372–391.
  38. W.B. Bradley and A.S. Kobayashi,Engineering Fracture Mechanics 3 (1971) 317–332.
    Google Scholar
  39. L.B. Freund, in_The Mechanics of Fracture_, 9ed. F. Erdogan, AMD-Vol. 19,ASME, New York (1976) 105–134.
    Google Scholar

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  1. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, CA, USA
    K. Ravi-Chandar & W. G. Knauss

Authors

  1. K. Ravi-Chandar
  2. W. G. Knauss

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Ravi-Chandar, K., Knauss, W.G. An experimental investigation into dynamic fracture: I. Crack initiation and arrest.Int J Fract 25, 247–262 (1984). https://doi.org/10.1007/BF00963460

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