Experimental Mechanics

, Volume 21, Issue 1, pp 41–48 | Cite as

Dynamic stress-intensity factors for unsymmetric dynamic isochromatics

The mixed-mode, near-field state of stress surrounding a constant-velocity crack is used in an overdeterministic, least-square procedure to determineKI,KII and σox from dynamic photoelastic patterns surrounding the running crack. The procedure is used to determine the mixed-mode stress-intensity factors associated with crack branching and crack curvingfrom dynamic photoelastic patterns surrounding the running crack. The procedure is used to determine the mixed-mode stress-intensity factors associated with crack branching and crack curving
  • A. S. Kobayashi
  • M. Ramulu
Article

Abstract

The mixed mode, near-field state of stresses sourrounding a crack propagating at constant velocity is used to derive a relation between the dynamic stress-intensity factorsKI,KII, the remote stress component σ ox and the dynamic isochromatics. This relation, together with an over-deterministic least-square method, form the basis of a datareduction procedure for extracting dynamic,KI,KII and σ ox from the recorded dynamic photoelastic pattern surrounding a running crack. The overdeterministic least-square method is also used to fit static isochromatics to the numerically generated dynamic isochromatics. The resultant staticKI,KII and σ ox are compared with the corresponding dynamic values and estimats of errors involved in using static analysis to process dynamic isochromatic data are obtained. The data-reduction procedure is then used to evaluate the branching stress-intensity factor associated with crack branching and the mixed-mode stress-intensity factors associated with crack curving.

Keywords

Mechanical Engineer Fluid Dynamics Constant Velocity Stress Component Mixed Mode 

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References

  1. 1.
    Dally, J.W., “Dynamic. Photoelastic Studies of Fracture,”Experimental Mechanics,19 (10),349–367 (Oct. 1979).CrossRefGoogle Scholar
  2. 2.
    Irwin, G.R., “Discussion of the Dynamic Stress Distribution Surrounding a Running Crack—A Photoelastic Analysis,”Proc. of SESA,16 (1),93–96 (1958).Google Scholar
  3. 3.
    Bradley, W.B. andKobayashi, A.S., “An Investigation of a Propagating Crack by Dynamic Photoelasticity,”Experimental Mechanics,10 (3),103–113 (1970).CrossRefGoogle Scholar
  4. 4.
    Bradley, W.B. andKobayashi, A.S., “Fracture Dynamics—A Photoelastic Investigation,”Eng. Fract. Mech.,3,317–332 (1971).Google Scholar
  5. 5.
    Kobayashi, T. and Dally, J.W., “The Relation Between Crack Velocity and Stress Intensity Factor in Birefringent Polymers,” Fast Fracture and Crack Arrest (edited by G.T. Hahn and M.F. Kanninen), ASTM STP 627, 257–273 (1977).Google Scholar
  6. 6.
    Kobayashi, A.S., Wade, B.G. andBradley, W.B., “Fracture Dynamics of Homalite-100,”Deformation and Fracture of High Polymers (edited by H.H. Kausch, J.A. Hassell andR.I. Jafee),Plenum Press, New York, 487–500 (1973).Google Scholar
  7. 7.
    Irwin, G.R., Dally, J.W., Kobayashi, T., Fourney, W.L., Etheridge, M.J. andRossmanith, H.P., “On the Determination of the »-K Relationships for Birefringent Polymers,”Experimental Mechanics,19 (4),121–128 (1979).CrossRefGoogle Scholar
  8. 8.
    Rossmanith, H.P. and Irwin, G.R., “Analysis of Dynamic Isochromatic Crack-Tip Stress Patterns,” University of Maryland Report (1979).Google Scholar
  9. 9.
    Smith, D.G. andSmith, C.W., “Photoelastic Determination of Mixed Mode Stress Intensity Factors,”Eng. Fract. Mech.,4 (2),357–366 (1972).Google Scholar
  10. 10.
    Smith, C.W., Jolles, M. and Peters, W.H., “Stress Intensities for Crack Emanating from Pin-Loaded Holes,” Flaw Growth and Fracture, ASTM STP 631, 190–201 (1977).Google Scholar
  11. 11.
    Gdoutos, E.E. andTheocaris, P.S., “A Photoelastic Determination of Mixed-mode Stress-intensity Factors,”Experimental Mechanics,18 (3),87–96 (March 1978).CrossRefGoogle Scholar
  12. 12.
    Dally, J.W. andSanford, R.J., “Classification of Stress-intensity Factors from Isochromatic-fringe Patterns,”Experimental Mechanics,18 (12),441–448 (Dec. 1978).CrossRefGoogle Scholar
  13. 13.
    Sanford, R.J. andDally, J.W., “A General Method for Determining Mixed-Mode Stress Intensity Factors from Isochromatic Fringe Patterns,”Eng. Fract. Mech.,11,621–633 (1979).Google Scholar
  14. 14.
    Klein, G., “Spanningsfaktoren eines Risses in der Umgebung eines Kreisloches und Ihr Einfluss auf das Bruchverhalten,”Zeitschrift für Werkstofftechnik,6 (1),30–34 (1975).Google Scholar
  15. 15.
    Iida, S. andKobayashi, A.S., “Crack Propagation Rate in 7075-T6 Plates Under Cyclic Tensile and Transverse Shear Loading,”J. of Basic Eng., Trans. of ASME,91,Series D (4),764–769 (Dec. 1964).Google Scholar
  16. 16.
    Freund, L.B. andClifton, R.J., “On the Uniqueness of Plane Elasto-dynamic Solutions for Running Cracks,”J. of Elasticity,4 (4),293–299 (Dec. 1974).Google Scholar
  17. 17.
    Freund, L.B., “Dynamic Crack Propagation,”The Mechanics of Fracture,19,edited by F. Erdogan ASME,105–134 (1976).Google Scholar
  18. 18.
    Freund, L.B., “The Mechanics of Dynamic Shear Crack Propagation,”J. of Geophysical Research,84 (35),2199–2209 (1978).Google Scholar
  19. 19.
    Etheridge, J.M., Dally, J.W. andKobayashi, T., “A New Method of Determining the Stress Intensity Factor K from Isochromatic Fringe Loops,”Eng. Fract. Mech.,10 (1),81–93 (1978).Google Scholar
  20. 20.
    Kobayashi, A.S. andMall, S., “Dynamic Fracture Toughness of Homalite-100,”Experimental Mechanics,18 (1).11–18 (Jan. 1978).CrossRefGoogle Scholar
  21. 21.
    Schroedl, M.A., McGowan, J.J., andSmith, C.W., “An Assessment of Factors Influencing Data Obtained by the Photoelastic Stress Freezing Technique for Stress Fields Near Crack Tips,”J. of Eng. Fract. Mech.,4,801–809 (1972).Google Scholar
  22. 22.
    Kobayashi, A.S., Wade, B.G., Bradley, W.B. andChiu, S.T., “Crack Branching in Homalite-100 Sheets,”Eng. Fract. Mech.,6,81–92 (1974).Google Scholar
  23. 23.
    Atluri, S.N., Kobayashi, A.S. andNakagaki, M., “An Assumed Displacement Hybrid Finite Element Model for Linear Fracture Mechanics,”International J. of Fract.,11,257–271 (1975).Google Scholar
  24. 24.
    Wade, B.G., “A Photoelastic and Numerical Study on Fracture Dynamics of Stressed Panels,” PhD thesis submitted to the University of Washington (1974).Google Scholar
  25. 25.
    Smith, C.W., “Stress Intensity and Flaw-shape Variations in Surface Flaws,” to be published in Experimental Mechanics.Google Scholar
  26. 26.
    Kalthoff, J.F., “On the Propagation Direction of Bifurcated Cracks,”Dynamic Crack Propagation (edited by G.C. Sih),Noordhoff International Leyden, 449–458 (1973).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1981

Authors and Affiliations

  • A. S. Kobayashi
    • 1
  • M. Ramulu
    • 1
  1. 1.Department of Mechanical Engineering, College of EngineeringUniversity of WashingtonSeattle

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