Modelling creep, ratchetting and failure in structural components subjected to thermo-mechanical loading

• Autorzy: Dunne F. P. E. , Lin J. , Hayhurst D. R. , Makin J.

Warianty tytułu

PL

Modelowanie pełzania, ratchetingu oraz zniszczenia elementów konstrukcyjnych poddawanych obciążeniom termo-mechanicznym

• Języki publikacji: EN

Abstrakty

EN

Experiments have been described in which copper components have been subjected to combined cyclic thermal and constant mechanical loading. Two thermal cycles were employed leading to predominantly cyclic plasticity damage and balanced creep - cyclic plasticity damage loading cycles. The combined loading led to component ratchetting and ultimately to failure. Continuum damage-based finite element techniques have been developed for combined cyclic plasticity, creep and ratchetting in components subjected to thermo-mechanical loading. Cycle jumping techniques have been employed within the finite element formulation to minimise computer CPU times. The finite element methods have been used to predict the behaviour of the copper components tested experimentally and the results compared. Steady-state ratchet rates were found to be well predicted by the models. Modes of failure and component lifetimes were also found to be reasonably well predicted. The experimental results demonstrate the importance of isotropic cyclic hardening on the initial component ratchetting rates.

PL

W pracy przedstawiono doświadczenia, w których miedziane elementy poddawano złożonym obciążeniom zawierającym cykle termiczne i obciążenia stałe. Zastosowano dwa cykle termiczne prowadzące do uszkodzenia z przewagą cyklicznej plastyczności i zrównoważonego pełzania oraz cykle obciążeń wywołujących uszkodzenie typowe dla cyklicznej plastyczności. Obciążenia złożone wywoływały ratcheting badanych elementów, a w efekcie końcowym zniszczenie. Techniki metody elementów skończonych kontynualnej mechaniki uszkodzeń zostały rozwinięte dla cyklicznej plastyczności w złożonym stanie naprężenia, pełzania oraz ratchetingu w elementach poddawanych obciążeniom termo-mechanicznym. W sformułowaniu metody elementów skończonych, aby zminimalizować czasy centralnego procesora (CPU) komputera, zastosowano techniki skoków cyklicznych. Metody elementów skończonych zastosowano w przewidywaniu zachowania się elementów miedzianych wcześniej badanych doświadczalnie, a otrzymane wyniki porównano. Zaproponowane modele w sposób satysfakcjonujący pozwalają przewidywać prędkości stanu ustalonego ratchetingu. Także przewidywania dotyczące sposobów zniszczenia oraz żywotności badanych elementów są zadowalające. Wyniki doświadczalne pokazują istotny wpływ izotropowego wzmocnienia cyklicznego na początkowe składowe prędkości ratchetingu.

Słowa kluczowe

EN

creep damage; cyclic plasticity damage; thermo-mechanical loading; FE modelling; thermo-mechanical testing

PL

obciążenia termomechaniczne; zniszczenia konstrukcji; cykle termiczne

• Wydawca: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
• Czasopismo: Journal of Theoretical and Applied Mechanics
• Rocznik: 2006
• Tom: Vol. 44 nr 3
• Strony: 667--689
• Opis fizyczny: Bibliogr. 35 poz., rys.

Twórcy

autor

Dunne F. P. E.

autor

Lin J.

autor

Hayhurst D. R.

autor

Makin J.

• Dwpartment of Engineering Science, Oxford University, UK,

Bibliografia

• 1. Benallal A., Ben Cheikh A., 1987, Constitutive equations for anisothermal elasto-viscoplasticity, In: Constitutive Laws for Engineering Materials; Theory and Applications, C. Desai, E. Krempl (edit.), 607-674
• 2. Benallal A., Marquis D., 1987, Constitutive equations for non-proportional cyclic elasto-viscoplasticity, J. Eng. Mater. Technol., 109
• 3. Blackman D.R., Socie D.F., Leckie F.A., 1983, Applications of continuum damage concepts to creep fatigue interactions, ASME Symp. on Thermal and Environmental Effects on Fatigue, Portland, 45-47
• 4. Bodner S.R., Partoum Y., 1975, Constitutive equations for elastoviscoplastic strain hardening materials, J. Appl. Mech., 97, 385-489
• 5. Chaboche J.L., 1987, Cyclic plasticity and ratchetting effects, In" 2nd Inst. Conf. on Constitutive Laws for Engineering Materials: Theory and Applications, University of Arizona, Tucson, USA
• 6. Chaboche J.L., 1988, Continuum damage mechanics. Part II. Damage growth, crack initiation and crack growth, J. Appl. Mech., 55, 65-72
• 7. Chaboche J.L., Rousellier G., 1983, On the plastic and viscoplastic constitutive equations. Part 1. Rules developed with internal variable concept, J. Press. Vessel Technol., 105, 153-158
• 8. Dunne F.P.E., Hayhurst D.R., 1992a, Continuum damage based constitutive equations for copper under high temperatures creep and cyclic plasticity, Proc. R. Soc. Lond., A437, 454-556
• 9. Dunne F.P.E., Hayhurst D.R., 1992b, Modelling of combined high temperature creep and cyclic plasticity in components using continuum damage mechanics, Proc. R. Soc. Lond., A437, 567-589
• 10. Dunne F.P.E., Hayhurst D.R., 1994, Eficient cycle jumping techniques for the modelling of materials and structures under cyclic mechanical and thermal loading, Eur. J. Mech., 13, 5, 639-660
• 11. Dunne F.P.E., Makin J., Hayhurst D.R., 1992, Automated procedures for the determination of high temperature viscoplastic damage constitutive equations, Proc. R. Soc. Lond., A437, 527-544
• 12. Dunne F.P.E., Puttergill D.B., Hayhurst D.R., Mabbutt Q.J., 1993, Experimental investigation of cyclic plasticity continuum damage evolution in an engineering components subjected to thermal loading, J. of Strain Anal., 28, 4, 263-272
• 13. Greenwood G., 1973, Creep life and ductility. Microstructures and the design of alloys, Int. Conf. on Metals, 2, 91-98
• 14. Hall F.R., Hayhurst D.R., 1991, Continuum damage mechanics modelling of high temperature deformation and failure in a pipe weldment, Proc. R. Soc. Lond., A433, 383-403
• 15. Hall F.R., Hayhurst D.R., Brown P.R., 1996, Prediction of plane strain creep-crack growth using continuum damage mechanics, Int. J. Damage Mech., 5, 353-383
• 16. Hayhurst D.R., 1972, Creep rupture under multi-axial states of stress, J. Mech. Phys. Solids., 20, 381-390
• 17. Hayhurst D.R., 1973, Stress redistribution and rupture due to creep in a uniformly stretched thin plate containing a circular hole, J. Appl. Mech., 1, 244-250
• 18. Hayhurst D.R., Brown P.R., Morrison C.J., 1984a, The role of continuum damage in creep crack growth, Phil. Trans. R. Soc. Lond., A311, 131-158
• 19. Hayhurst D.R., Dimmer P.R., Morrison C.J., 1984b, Development of continuum damage in the creep rupture of notched bars, Phil. Trans. R. Soc. Lond., A311, 103-129
• 20. Hayhurst D.R., Hayhurst R.J., Vakili-Tahami F., 2005a, CMD predictions of creep damage initiation and growth in ferritic steel weldments in a medium bore branched pipe under constant pressure at 590°C using a 5-material weld model, Proc. R. Soc. Lond., A461, 2303-2326
• 21. Hayhurst D.R., Makin J., Wong M.T., Xu Q., 2005b, Modelling of combined creep and cyclic plasticity in a model component undergoing ratchetting using continuum damage mechanics, Philosophical Magazine, 85, 16, 1701-1728
• 22. Inoue T., Igari T., Yoshida F., Suzuki A., Murkami S., 1985, Inelastic behaviour of 2.25Cr-1Mo steel under plasticity-creep interaction conditions, Nucl. Eng. Des., 90, 287
• 23. Kujowski P., Mróz Z., 1980, A viscoplastic material model and its applications to cyclic loading, Acta Mechanica, 36, 213-130
• 24. Johanssan G., Ekh M., Runessan K., 2005, Computational modelling of inelastic large ratchetting strains, Int. J. Plasticity, 21, 5, 955-980
• 25. Lemaitre P.M., Chaboche J.L., 1990, Mechanics of Solid Materials, Cambridge University Press
• 26. Lemaitre P.M., Plumtree A., 1979, Applications of damage concepts to predict creep-fatigue failure, J. Eng. Mater. Technol., 101, 284-292
• 27. Lesne P.M., Chaboche J.L., 1984, Predictions of crack initiation under thermal fatigue and creep, In: 2nd Int. Conf. on Fatigue and Creep, Fatigue 84, Birmingham, UK
• 28. Lin J., Dunne F.P.E., Hayhurst D.R., 1996, Physically-based temperature dependence of elasto-viscoplastic constitutive equations for copper between 20 and 500°C, Philos. Mag., 74, 2, 359-382
• 29. Lin J., Dunne F.P.E., Hayhurst D.R., 1997, Approximate method for the analysis of components undergoing ratchetting and failure, J. of Strain Analysis, 33, 1, 55-65
• 30. Lin J., Dunne F.P.E., Hayhurst D.R., 1999, Aspects of testpiece design responsible for errors in cyclic plasticity experiments, Int. J. of Damage Mechanics, 8, 2, 109-137
• 31. Liu M.C.M., Krempl E., 1979, A uni-axial viscoplastic model based on total stress and overstress, J. Mech. Phys. Solids, 7, 377-391
• 32. Manonukul A., Dunne F.P.E., Knowles D., Williams S., 2005, Multiaxial creep and cyclic plasticity in nickel-base alloy C263, Int. J. of Plasticity, 21, 1-20
• 33. Miller A., 1979, An inelastic constitutive model for monotonic cyclic and creep deformation. Part 1. Equations development and analytical procedures, J. Eng. Mater. Technol., 98, 97-105
• 34. Remy L., Skelton P., 1990, Damage assessment of component experiencing thermal transients, In: Proc. Int. Conf. on High Temp. Structural Design, CEC, Venice. Bury St Edmunds: MEP
• 35. Wang Z.P., Hayhurst D.R., 1994, The use of super-computer modelling of high temperature failure in pipe weldments to optimise weld and heat affected zone material property selection, Proc. R. Soc. Lond., A446, 127-148