Fatigue Life Estimation of Welded Joints by using Mk-factor under a Propagation Mechanism of Multiple Collinear Surface Cracks

Mk-계수를 고려한 용접부 복수 표면균열 진전수명 평가

  • 한승호 (한국기계연구원 구조연구부) ;
  • 한정우 (한국기계연구원 구조연구) ;
  • 신병천 (한국기계연구원 구조연구) ;
  • 김재훈 (충남대학교 기계설계공학과)
  • Published : 2004.08.01

Abstract

Failure mechanisms of welded joints under fatigue loads are interpreted that multiple collinear surface cracks initiating randomly along the weld toes propagate under the mutual interaction and coalescence of adjacent two cracks. To estimate fatigue crack propagation life for three types of the representative welded joints, i.e. non-load carrying cruciform, cover plate and longitudinal stiffener joint, the stress intensity factors at the front of the surface cracks have to be calculated, which are influenced strongly by the geometry of attachments, weld toes and the crack shapes. For the effective calculation of the stress intensity factors the Mk-factor was introduced which can be derived by a parametric study performed by FEM considering influence of the geometrical effects. The fatigue life of the cruciform joint was estimated by using the Mk-factors and the method considering the propagation mechanisms of the multiple surface cracks. Analysis results for the fatigue life had a good agreement with that of experiment.

Keywords

References

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