Improvement of Fatigue Strength by Spot Heating for Out-of-plane Gusset

국부가열을 이용한 면외거셋의 피로강도 향상

  • 정영화 (강원대학교 토목공학과) ;
  • 남왕현 (강원대학교 대학원 토목공학과) ;
  • 장동휘 (강원대학교 대학원 토목공학과)
  • Published : 2001.12.31

Abstract

In the study, the fatigue strength improvement and mechanism have been estimated by the Spot-Heating treatment on welded bead toes. For this, web-gusset specimens were made without residual stresses and the others with residual stresses imposed by Spot-Heating. The 4-point bending tests were performed in order to estimate the effect of spot-heating on fatigue strength and fatigue characteristics quantitatively for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue test, fatigue strength of As-Welded specimen for non load-carrying fillet welded joints subjected to pure bending has satisfied the grade of fatigue prescribed in specifications of korea, AASHTO and JSSC. As compare with As-Welded specimen and Spot-Heating specimen have increased about 20% for the fatigue strength at $7.7{\times}10^6$ cycles. The Spot-Heating by reformation of the residual stress on welded bead toes has greatly affected the fatigue crack propagation life, but has slightly affected the fatigue crack initiation life.

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