• Kim, Jong-Min (Department of Mechanical Engineering, Sungkyunkwan University) ;
  • Huh, Nam-Su (School of Mechanical Design and Automation Engineering Seoul National University of Science and Technology)
  • Received : 2010.08.02
  • Accepted : 2010.11.04
  • Published : 2010.12.31


The crack-tip stress fields and fracture mechanics assessment parameters for a surface crack, such as the elastic stress intensity factor or the elastic-plastic J-integral, can be affected significantly by the adjacent cracks. Such a crack interaction effect due to multiple cracks can alter the fracture mechanics assessment parameters significantly. There are many factors to be considered, for instance the relative distance between adjacent cracks, the crack shape, and the loading condition, to quantify the crack interaction effect on the fracture mechanics assessment parameters. Thus, the current assessment codes on crack interaction effects (crack combination rules), including ASME Sec. XI, BS7910, British Energy R6 and API 579-1/ASME FFS-1, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates crack interaction effects by evaluating the elastic stress intensity factor and the elastic-plastic J-integral of adjacent in-plane surface cracks in a plate through detailed 3-dimensional elastic and elastic-plastic finite element analyses. The effects on the fracture mechanics assessment parameters of the geometric parameters, the relative distance between two cracks, and the crack shape are investigated systematically. As for the loading condition, an axial tension is considered. Based on the finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks are discussed. The present results can be used to develop more concrete guidance on crack interaction effects for crack shape characterization to evaluate the integrity of defective components.


  1. J. R. Rice, 1968, “A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks,” Journal of Applied Mechanics, Vol. 35, pp. 379-386.
  2. ASME, 2007, “Rules for In-Service Inspection of Nuclear Power Plant Components,” ASME Sec. XI, Division 1, IWA-3000.
  3. American Petroleum Institute, 2007, “Fitness-for-Service,” API 579-1/ASME FFS-1.
  4. British Standard Institute, 1999, “Guide on Methods for Assessing the Acceptability of Flaws in Fusion Welded Structures,” BS7910, London.
  5. British Energy, 2001, “R6: Assessment of the Integrity of Structures Containing Defects,” Revision 4.
  6. Y. Murakami and S. Nemat-Nsasser, 1982, “Interacting Disssimilar Semi-Elliptical Surface Flaws under Tension and Bending,” Engineering Fracture Mechanics, Vol. 16, pp. 373-386.
  7. T. Miyoshi, M. Shiratori and O. Tanabe, 1985, “Stress Intensity Factors for Surface Cracks with Arbitrary Shapes in Plates and Shells,” Fracture Mechanics: Sixteenth Symposium, ASTM STP 868, M.F. Kanninen and A.T. Hopper, Eds., American Society for Testing and Materials, Philadelphia, pp. 521-534.
  8. K. Hasegawa, K. Miyazaki and S. Kanno, 2001, “Interaction Criteria for Multiple Flaws on the basis of Stress Intensity Factors,” ASME Pressure Vessels and Piping Conference, Vol. 422, pp. 23-29.
  9. M. Kamaya, 2005, “Influence of the Interaction on Stress Intensity Factor of Semi-Elliptical Surface Cracks,” ASME Pressure Vessels and Piping Conference, PVP2005-71352.
  10. N. S. Huh, D. J. Shim, S. Choi, G. M. Wilkowski and J. S. Yang, 2008, “Stress Intensity Factors for Slanted Through-Wall Cracks based on Elastic Finite Element Analyses,” Fatigue and Fracture of Engineering Materials and Structures, Vol. 31, pp. 197-208.
  11. ABAQUS, Inc., “User’s Manual,” ABAQUS Version 6.7-1, 2007.
  12. T. Nakamura and D. M. Parks, 1991, “Determination of Elastic T-Stress along 3-D Crack Fronts using an Interaction Integral,” International Journal of Solids and Structures, Vol. 29, pp. 1597-1611.
  13. I. S. Raju and J. C. Newman, 1979, “Stress Intensity Factors for a Wide Range of Semi-Elliptical Surface Cracks in Finite-Thickness Plates,” Engineering Fracture Mechanics, Vol. 11, pp. 817-829
  14. T. Fett and D. Munz, 1997, “Stress Intensity Factors and Weight Functions,” Computational Mechanics Publications.

Cited by

  1. Biaxial Tension of a Piecewise Homogeneous Plate with Two Cracks on the Interface of Materials with Regard for the Plastic Zones Near their Tips vol.50, pp.6, 2015,
  2. Evaluation of J Integral for Interacting Twin Collinear Through-Wall Cracks in a Plate under Tension vol.665, pp.1662-9795, 2015,