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Modeling Creep Behavior and Life by Damage Mechanics

손상역학에 의한 크리프 거동 및 수명 모델링

  • Published : 2000.07.01

Abstract

Commercially pure copper is tested to obtain creep curves at 2500C. Constitutive relations adopting continuum damage mechanics concept is found to be appropriate to model the creep defor mation up to the tertiary stage. Microscopic observation by SEM reveals that creep condition induces cavities and microcracks subsequently. The constitutive equations along with evaluated creep parameters are implemented into finite element analysis code. The analysis reproduces creep curves under step loading as well as constant loading with reasonable accuracy. Distribution and evolution of damage under creep loading are numerically simulated for two different types of notched specimen. Predicted creep life agrees quite well with rupture test results. The influence of mesh size at notch tip on rupture time prediction is studied, and a degree of refinement is suggested for the specific notched specimens.

Keywords

Creep;Copper;Damage Mechanics;FEM

References

  1. Masuyama, F., Nishimura, N. and Igari, T., 1990, 'Creep Damage Simulation Test and Creep Lift Assessment System for Elevated Temperature Plant Components,' ISIJ International, Vol. 30, No. 10, pp. 885-894
  2. Sklenicka, V., Lukas, P. and Kunz, L., 1990, 'Intergranular Fracture in Copper under High Temperature Creep, Fatigue and Creep-Fatigue Conditions,' Scripta Metall. et Materialia, Vol. 24, pp. 1795-1800 https://doi.org/10.1016/0956-716X(90)90548-U
  3. Murakami, S., Kawai, M. and Rong, H., 1988, 'Finite Element Analysis of Creep Crack Growth by a Local Approach,' Int. J. Mech. Sci., Vol. 30, No. 7, pp. 491-502 https://doi.org/10.1016/0020-7403(88)90003-3
  4. Liu, Y. and Murakami, S., 1998, 'Damage Localization of Conventional Creep Damage Models and Propagation of a New Model for Creep Damage Analysis,' JSME International Journal, Vol. 41, No. 1, pp. 57-65
  5. Leckie, F.A. and Hayhurst, D.R., 1977, 'Constitutive Equations of Creep Rupture,' Acta Metall., Vol. 25, pp. 1059-1070 https://doi.org/10.1016/0001-6160(77)90135-3
  6. Kachanov, L.M., 1958, 'The Time to Failure under Creep Condition,' Izv. Akad. Nauk, SSSR. Tekh. Nauk, Vol. 8, pp. 26-31
  7. Tvergaard, V., 1984, 'On the Creep Constrained Diffesive Cavitation of Grain-Boundary Faccts,' J. of the Mechanics and Physics of Solids, Vol. 32, No. 5, pp. 373-393 https://doi.org/10.1016/0022-5096(84)90021-8
  8. Wang, J.S. and Nix, W.D., 1987, 'A Numerical Model for Prediction of Creep Fracture,' Materials Science and Engineering, Vol. 89, pp. 73-80 https://doi.org/10.1016/0025-5416(87)90251-5
  9. Hutchinson, J.W., 1983, 'Constitutive Behavior and Crack Tip Fields for Materials Undergoing Creep-Constrained Grain Boundary Cavitation,' Acta Metall., Vol. 31, No.7, pp. 1079-1088 https://doi.org/10.1016/0001-6160(83)90204-3
  10. Benci, J. E., Pope, D.P., and Bassani, J.L., 1994, 'a Combined Experimental and Analytical Investigation of Creep Damage Development in Copper,' Acta Metall. Vol. 42, No. 1, pp. 225-238 https://doi.org/10.1016/0956-7151(94)90065-5
  11. Murakami, S. and Liu, Y., 1995, 'Mesh-dependence in Local Approach to Creep Fracture,' Int. J. of Damage Mech., Vol. 4, No. 3, pp. 230-250 https://doi.org/10.1177/105678959500400303
  12. Krajcinovic, D., 1996, Damage Mechanics, Elsevier, pp. 474-483
  13. Lemaitre, J., 1996, A Course on Damage Mechanics, 2nd Ed. Springer, pp. 117-126
  14. Needleman, A. and Tvergaard, V., 1994, 'Mesh Effects in the Analysis of Dynamic Ductile Crack Growth,' Engineering Fracture Mechanics, Vol. 47, No. 1, pp. 75-91 https://doi.org/10.1016/0013-7944(94)90239-9
  15. 윤기봉, 1997, '산업설비의 수명평가 기술,산업설비 안전성평가 연구센터, 성균관대학교, pp. 65-97