Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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Evaluation of Residual Stress Effect about Fatigue Characteristic of U-shaped Structure

U자형 구조의 피로특성에 대한 잔류응력의 영향 평가

  • Kim, Sang-Young (Graduate School of Mechanical Engineering, Sungkyunkwan Univ.) ;
  • Koo, Jae-Mean (Department of Mechanical Engineering, Sungkyunkwan Univ.) ;
  • Seok, Chang-Sung (Department of Mechanical Engineering, Sungkyunkwan Univ.) ;
  • Mo, Jin-Yong (Mechanical Core Technology Group, DA Network Business, Samsung Electronics Co., Ltd)
  • 김상영 (성균관대학교 기계공학부 일반대학원) ;
  • 구재민 (성균관대학교 기계공학부) ;
  • 석창성 (성균관대학교 기계공학부) ;
  • 모진용 (삼성전자 DA 총괄)
  • Received : 2009.11.26
  • Accepted : 2010.02.24
  • Published : 2010.04.01
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Abstract

Mechanical structures with power sources experience repeated force produced by motors. In result, the life of the pipes reduces and ultimately, the pipes collapse. Such pipes are formed into several shapes and particularly, the U-shape pipe is damaged frequently. In most cases, the U-shape pipe is made with a straight pipe by complicated bending work. During this work process, plastic deformation of the pipe produces residual stress in the pipe. This residual stress significantly affects the fracture behavior of the pipe and induces the change of the stress ratio (min. stress/Max. stress = R). For this reason, residual stress has to be evaluated. In this paper, the residual stress of a U-shaped pipe was evaluated by FEM analysis. In addition, fatigue tests of the U-shaped pipe were performed by using a uniaxial fatigue testing machine. The results of the fatigue test were modified with the results of FEM (Finite Element Method) analysis for residual stress. The modified fatigue test results of the U-shaped pipe were compared with those of a straight pipe.

Keywords

References

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