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Estimation Method of Local Elastic-Plastic Strain at Thinning Area of Straight Pipe Under Tension Loading

인장하중을 받는 직선 배관 감육부의 국부 탄소성 변형률 평가 방법

  • 안중혁 (고려대학교 대학원 기계공학부) ;
  • 김윤재 (고려대학교 기계공학부) ;
  • 윤기봉 (중앙대학교 기계공학부) ;
  • 마영화 (중앙대학교 대학원 기계공학부)
  • Published : 2006.05.01

Abstract

In order to assess the integrity of pipes with local thinning area, the plastic strain as well as the elastic strain at the root of thinned region are required particularly when fluctuating load is applied to the pipe. For estimating elastic-plastic strain at local wall thinning area in a straight pipe under tensile load, an estimation model with idealized fully circumferential constant depth wall thinning area is proposed. Based on the compatibility and equilibrium equations a nonlinear estimation equation, from which local elastic-plastic strain can be determined as a function of pipe/defect geometry, material and the applied strain was derived. Estimation results are compared with those from detailed elastic-plastic finite element analysis, which shows good agreements. Noting that practical wall thinning in nuclear piping has not only a circular shape but also a finite circumferential length, the proposed solution for the ideal geometry is extended based on two-dimensional and three-dimensional numerical analysis of pipes with circular wall thinning.

Keywords

Local Wall Thinning;Local Eastic-Plastic Strain;Finite Element Analysis;Erosion Assisted Corrosion

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