DOI QR코드

DOI QR Code

Constraint of Semi-elliptical Surface Cracks in T and L-joints

T-형 및 L-형 배관내 반타원 표면균열에서의 구속상태

  • Lee, Hyeong-Il
  • 이형일
  • Published : 2001.09.01

Abstract

Critical defects in pressure vessels and pipes are generally found in the form of a semi-elliptical surface crack, and the analysis of which is consequently an important problem in engineering fracture mechanics. Furthermore, in addition to the traditional single parameter K or J-integral, the second parameter like T-stress should be measured to quantify the constraint effect. In this work, the validity of the line-spring finite element is investigated by comparing line-spring J-T solutions to the reference 3D finite element J-T solutions. A full 3D-mesh generating program for semi-elliptical surface cracks is employed to provide such reference 3D solutions. Then some structural characteristics of the surface-cracked T and L-joints are studied by mixed mode line-spring finite element. Negative T-stresses observed in T and L-joints indicate the necessity of J-T two parameter approach for analyses of surface-cracked T and L-joints.

Keywords

Semi-elliptical Surface Crack;Finite Element Analysis;Line-spring Finite Element;J-integral;T-stress;T-joint;L-joint

References

  1. ABAQUS User's Manual, 1999, Version 5.8 Hibbitt, Karlsson and Sorensen, Inc., Pawtucket, RI
  2. Nakamura, T. and Parks, D. M., 1992, Three-Dimensional Stress Field Near the Crack Front of a Thin Elastic Plate, Journal of Applied Mechanics, Vol. 55, pp. 805-813
  3. Parks, D. M., 1977, 'The Virtual Crack Extension Method for Nonlinear Material Behavior,' Computer Methods in Applied Mechanics and Engineering, Vol. 12, pp. 353-364 https://doi.org/10.1016/0045-7825(77)90023-8
  4. Shih, C. F., Moran, B. and Nakamura, T., 1986, 'Energy Release Rate along a Three-Dimensional Crack Front in a Thermo-Mechanical Field,' International Journal of Fracture, Vol. 30, pp. 79-102 https://doi.org/10.1007/BF00034019
  5. 이형일, 한태수, 정재헌, 2000, 결함해석에 기초한 배관용접부 수명평가,' 대한기계학회논문집 (A), 제24권, 제5호, pp. 1331-1342
  6. White, C. S., Ritchie, R. O. and Parks, D. M., 1983, 'Ductile Growth of Part-through Surface Cracks : Experiment and Analysis,' Elastic-Plastic Fracture:Second Symposium, Vol. I -Inelastic Crack Analysis Edited by Shih, C. F. and Gudas, J. P., ASTM STP 803, pp. 1384-1409
  7. Lee, H. and Parks, D. M., 1995, 'Enhanced Elastic-Plastic Line-Spring Finite Element,' International Journal of Solids and Structures, Vol. 32, pp. 2393-2418 https://doi.org/10.1016/0020-7683(94)00187-2
  8. Rice, J. R., 1972, 'The Line-spring Model for Surface Flaws,' The Surface Crack : Physical Problems and Computational Solutions, Edited by Swedlow, J. L., American Society of Mechanical Engineers, New York, pp. 171-185
  9. Desvaux, G. J., 1985, The Line Spring Model for Surface Flaw : An Extension to Mode II and Mode III, Chapters 2-3, Master Thesis, Department of Mechanical Engineering, Massachusetts Institute of Technology
  10. Wang, Y.-Y., 1991, A Two-parameter Characterization of Elastic-plastic Crack Tip Fields and Applications to Cleavage Fracture, Chapters 1-4, Ph. D. Dissertation, Department of Mechanical Engineering, Massachusetts Institute of Technology
  11. 이형일, 서헌, 2000, '용접부 3차원 표면균열선단에서의 구속상태,' 대한기계학회논문집 (A), 제24권, 제1호, pp. 144-155
  12. Rice, J. R. and Lery, N., 1972, 'The Part-through Surface Crack in an Elastic Plate,' Journal of Applied Mechanics, Vol. 39, pp. 185-194
  13. Parks, D. M., 1981, 'The Inelastic Line-Spring: Estimates of Elastic Fracture Mechanics Parameters for Surface-Cracked Plates and Shells,' Journal of Pressure Vessel Technology, Vol. 103, pp. 246-254
  14. Parks, D. M. and White, C. S., 1982, 'Elastic-Plastic Line-Spring Finite Elements for Surface-Cracked Plates and Shells,' Journal of Pressure Vessel Technology, Vol. 104, pp. 287-292
  15. Betegon, C.;Hancock, J. W., 1991, 'Two-parameter Characterization of Elastic-plastic Crack Tip Fields,' Journal of Applied Mechanics, Vol. 58, pp. 104-110
  16. Rice, J. R., 1974, 'Limitations to the Small-scale Yieding Approximation for Crack-tip Plasticity,' Journal of the Mechanics and Physics of Solids, Vol. 22, pp. 17-26 https://doi.org/10.1016/0022-5096(74)90010-6
  17. Larsson, S. G. and Carlsson, A. J., 1973, 'Influence of Non-singular Stress Terms and Specimen Geometry on Small-scale Yielding at Crack Tips in Elastic-plastic Material,' Journal of the Mechanics and Physics of Solids, Vol. 21, pp. 263-277 https://doi.org/10.1016/0022-5096(73)90024-0
  18. Williams, M. L., 1957, 'On the Stress Distribution at the Base of a Stationary Crack,' Journal of Applied Mechanics, Vol. 24, pp. 111-114