Papers by Keyword: Bend Angle

Abstract: Many empirical formulas and diagrams have been employed to determine resistance coefficient of elbow/bend pipes. However, a big discrepancy of calculation results obtained from these formulas/diagrams exists. So it is difficult for users to choose an appropriate formula to calculate resistance coefficient of an elbow/bend pipe. In this paper, a comparison of several common formulas was made. And variations of resistance coefficient with both bend angle and curvature radius were graphically shown for reference of selection. In addition, flow characteristics in elbow pipe were analyzed.

Abstract: A piping system including straight pipes, elbows and tee branches in a nuclear power plant is mostly subjected to severe loading conditions with high temperature and pressure. In particular, the wall-thinning of an elbow due to flow accelerated corrosion is one of safety issues in the nuclear industry. In this respect, it is necessary to investigate the limit loads of an elbow with a wall-thinned part for evaluating integrity. In this paper, three dimensional plastic limit analyses are performed to obtain limit loads of an elbow with different bend angles as well as defect geometries under internal pressure and in-plane/out-of-plane bending moment. The limit loads are also compared with the results from limit load solutions of an uninjured elbow based on the von Mises yield criteria. Finally, the effects of significant factors, bend angle and defect shape, are quantified to estimate the exact load carrying capacity of an elbow during operation.