Dislocation distribution in the plastic zone and growth of a short fatigue crack

• Autorzy: Bjerkén C. , Melin S.
• Konferencja: Konferencja mechaniki pękania / sympozjum (X ; 11-14.09.2005 ; Opole-Wisła, Polska)
• Języki publikacji: EN

Abstrakty

EN

The growth of a short edge crack under fatigue loading is investigated in detail for more than 11 000 cycles. The developing local plasticity consists of discrete dislocations that are emitted from the crack tip. The edge crack is modelled by a distribution of dislocation dipoles. The competition between global loading and local shielding of the crack tip governs the crack growth. The material modelled is BCC iron and the load is varied with a stress ratio R=-1. The growth rate increases in discrete steps with short periods of retardation from approx. The size of Burgers vector, b, per cycle up to 17 b. The plastic zone changes from having an elongating slender form to include a low-angle boundary.

Słowa kluczowe

EN

fatigue crack; plastic zone

• Wydawca: Oficyna Wydawnicza Politechniki Opolskiej
• Czasopismo: Zeszyty Naukowe. Mechanika / Politechnika Opolska
• Rocznik: 2005
• Tom: z. 82
• Strony: 29--36
• Opis fizyczny: Bibliogr. 12 poz., rys., tab.

Twórcy

autor

Bjerkén C.

• Malmö University College, Sweden

autor

Melin S.

• Lund University, Sweden

Bibliografia

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• [3] ANDERSSON H., PERSSON C: In-situ SEM study of fatigue crack growth behaviour in IN718, Int. J. Fatigue 26, 2004, 211-219.
• [4] BJERKEN C, MELIN S.: A tool to model short crack fatigue growth using a discrete dislocation formulation, Int. J. Fatigue 25, 2003, pp. 559-566.
• [5] BJERKEN C, MELIN S.: Propagation of a short fatigue crack modelled by a boundary element approach, Proc. 8* Int. Fatigue Congress, 3-7 June, 2002, Stockholm, Sweden, pp. 2053-2060.
• [6] BJERKEN C, MELIN S.: A study of the influence of grain boundaries on short crack growth during varying load using a dislocation techniąue, Engng Fract. Mech. 71, 2004, pp. 2215-2227.
• [7] BJERKEN C, MELIN S.: The influence of grain boundary orientation on fatigue growth of a short crack in the vicinity of a grain boundary, Proc. 91h Int. Conf. Mechanical Behaviour of Materials, May 25-29, 2003, Geneva, Switzerland.
• [8] BJERKEN C, MELIN S.: Influence of varying load spectra on short crack growth, Proc. 15th Euro. Conf. Fracture, Aug 2004, Stockholm, Sweden.
• [9] BJERKEN C: The discrete naturę of the growth and arrest of microstructurally short fatigue cracks modelled by dislocation technique, Int. J. Fatigue 27, 2005, pp. 21-32.
• [10] ASM Handbook, Vol. 2, ASM International, USA, 1990.
• [11] RIEMELMOSER F.O., PIPPAN R., STUWE H.P.: A comparison of a discrete dislocation model and a continuous description of cyclic crack tip plasticity, Int. J. Fracture 85, 1997, pp. 157-168.
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