Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Effect of Specimen Orientation on Fatigue Crack Growth Behavior in Friction Stir Welded Al7075-T651 Joints

마찰교반용접된 Al7075-T651 용접부의 피로균열전파 거동에 미치는 시험편 채취방향의 영향

  • Jeong, Yeui Han (Graduate School of Mechanical Design Engineering, Pukyong Nat'l Univ.) ;
  • Kim, Seon Jin (Dept. of Mechanical & Automotive Engineering, Pukyong Nat'l Univ.)
  • 정의한 (부경대학교 대학원 기계설계공학과) ;
  • 김선진 (부경대학교 기계자동차공학과)
  • Received : 2014.02.04
  • Accepted : 2014.08.18
  • Published : 2014.12.01
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Abstract

The aim of this paper is to investigate the effects of crack orientation on fatigue crack growth behavior in friction stir welded (FSWed) Al 7075-T651. Fatigue crack growth testing was conducted on compact tension (CT) specimens machined from the friction stir welds and the base metal under constant stress intensity factor range control. Tests were performed with the crack propagating nominally perpendicular to the weld line (termed the TL specimen) and the crack propagating in a parallel direction of the weld line (termed the LT specimen), and with three different constant stress intensity factor ranges. Both these specimen orientations were found to have a considerable effect on the fatigue crack growth behavior. Paris's law was adopted for the analysis of experimental results; the exponent m of the WM-LT specimen was determined to be 3.56, which was the largest value in this experimental conditions.

본 연구의 목적은 마찰교반용접된 Al7075-T651의 피로균열전파 거동에 미치는 시험편의 채취방향의 영향을 고찰하기 위한 것이다. 피로균열전파 실험은 마찰교반용접된 공시재로부터 모재와 용접재에 대하여 CT 시험편을 채취하여 일정응력확대계수범위 제어하에서 수행되었다. 균열이 용접선에 수직하여 전파하는 것(TL 시험편으로 명명)과 균열이 용접선과 나란히 전파하는 시험편(LT 시험편으로 명명)에 대하여 3가지 다른 응력확대계수범위에서 실험이 수행되었다. 시험편의 채취 방향에 따라 피로균열전파거동에 주요한 영향을 미침을 알 수 있었다. Paris 법칙에 적합시킨 결과 지수 m값은 WM-LT 시험편이 3.56으로 가장 높게 나타났다.

Keywords

References

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