Stress Intensity factor Calculation for the Axial Semi-Elliptical Surface Flaws on the Thin-Wall Cylinder Using Influence Coefficients

영향계수를 이용한 원통용기 축방향 표면결함의 응력확대계수의 계산

  • 장창희 (전력연구원 원자력연구원) ;
  • 문호림 (전력연구원 원자력연구원) ;
  • 정일석 (전력연구원 원자력연구원) ;
  • 김태룡 (전력연구원 원자력연구원)
  • Published : 2002.11.01


For integrity analysis of nuclear reactor pressure vessel, including the Pressurized thermal shock analysis, the fast and accurate calculation of the stress intensity factor at the crack tip is needed. For this, a simple approximation scheme is developed and the resulting stress intensity factors for axial semi-elliptical cracks in cylindrical vessel under various loading conditions are compared with those of the finite element method and other approximation methods, such as Raju-Newman's equation and ASME Sec. Xl approach. For these, three-dimensional finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R = 0.1. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite clement analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. The approximation solutions are within $\pm$2.5% of the those of FEA using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the VINTIN method provides sufficiently accurate stress intensity factor values for axial semi-elliptical flaws on the surface of the reactor pressure vessel.


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