Comparison of the continuum damage and fracture mechanics in fatigue assessment of components containing residual stresses

• M. J. Attarha ^[1] ; I. Sattari-Far ^[1]
  1. [1] Amirkabir University of Technology

     Amirkabir University of Technology

     Irán

     
• Localización: Mechanics based design of structures and machines, ISSN 1539-7734, Vol. 52, Nº. 8, 2024, págs. 5518-5535
• Idioma: inglés
• Enlaces
  • Texto completo
• Resumen

  • In the present study, the fatigue crack growth life of standard and smooth notched specimens containing residual stresses are evaluated based on the continuum damage and fracture mechanics approaches. It is indicated that fatigue crack growth lives assessed by the continuum damage model are closer to the experimental results, with a difference of <10% in the specimens containing residual stresses. The total stress intensity factor range is used to consider the effects of residual stresses in the estimation of fatigue crack growth life based on the fracture mechanics. It is found that in existing residual stresses, the stress intensity factor K is not a proper parameter to evaluate crack tip zone. Fatigue crack initiation life is experimentally obtained based on assessing variations of the slope of unloading curve in the force-displacement diagram of fatigue experiments. The cycle including a change in the slope is considered as fatigue crack initiation event. Isotropic and kinematic hardening parameters of ASTM A516 pressure vessel steel are considered in finite element analyses. Tensile residual stresses are introduced into the notched specimens by employing four-point-bending with a magnitude of around 90% of the yield stress of the material. The results indicate that at least 65% of the fatigue life of the specimens is decreased due to the presence of tensile residual stresses. Tensile residual stresses are measured using the hole-drilling technique.