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Fatigue Life Estimation of Welded Components Considering Welding Residual Stress Relaxation and Its Mean Stress Effect

잔류응력 이완 및 이의 평균응력 효과를 고려한 용접부 피로수명 평가

  • 한승호 (한국기계연구원 구조연구부) ;
  • 한정우 (한국기계연구원 구조연구부) ;
  • 신병천 (한국기계연구원 구조연구부) ;
  • 김재훈 (충남대학교 기계설계공학과)
  • Published : 2003.01.01

Abstract

The fatigue life of welded joints is sensitive to welding residual stress and complexity of their geometric shapes. To predict the fatigue life more reasonably. the effects of welding residual stress and its relaxation on their fatigue strengths should be considered quantitatively, which are often regarded to be equivalent to the effects of mean stresses by external loads. The hot-spot stress concept should be also adopted which can reduce the dependence of fatigue strengths for various welding details. Considering the factors mentioned above, a fatigue life prediction model using the modified Goodman's diagram was proposed. In this model, an equivalent stress was introduced which is composed of the mean stress based on the hot-spot stress concept and the relaxed welding residual stress. From the verification of the proposed model to real welding details, it is proved that this model can be applied to predict reasonably their fatigue lives.

Keywords

Fatigue Life;Welding Residual Stress;Stress Relaxation;Hot-Spot Stress;Equivalent Stress

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