Effects of Pipe Curvature and Internal Pressure on Stiffness and Buckling Phenomenon of Circular Thin-Walled Pipes

Authors: V. Polenta, S. D. Garvey, D. Chronopoulos, A. C. Long, H. P. Morvan

Abstract:

A parametric study on circular thin-walled pipes subjected to pure bending is performed. Both straight and curved pipes are considered. Ratio D/t, initial pipe curvature and internal pressure are the parameters varying in the analyses. The study is mainly FEA-based. It is found that negative curvatures (opposite to bending moment) considerably increase stiffness and buckling limit of the pipe when no internal pressure is acting and, similarly, positive curvatures decrease the stiffness and buckling limit. For internal pressurised pipes the effects of initial pipe curvature are less relevant. Results show that this phenomenon is in relationship with the cross-section deformation due to bending moment, which undergoes relevant ovalisation for no pressurised pipes and little ovalisation for pressurised pipes.

Keywords: Buckling, curved pipes, internal pressure, ovalisation, pure bending, thin-walled pipes.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1338096

References:

[1] S. P. Timoshenko and J. M. Gere, “Theory of elastic stability,” 1961.
[2] G. Bryan, “On the stability of a plane plate under thrusts in its own plane, with applications to the buckling of the sides of a ship,” Proceedings of the London Mathematical Society, vol. 1, no. 1, pp. 54–67, 1890.
[3] S. R. Hauch and Y. Bai, “Bending moment capacity of pipes,” Journal of Offshore Mechanics and Arctic Engineering, vol. 122, no. 4, pp. 243–252, 2000.
[4] K. Mørk, J. Spiten, E. Torselletti, O. Ness, and R. Verley, “The superb project and dnv’96: Buckling and collapse limit state,” in Proceedings of the International Conference on Offshore Mechanics and Artic Engineerinng. American Society of Mechanical Engineers, 1997, pp. 79–90.
[5] J. Hutchinson, “Axial buckling of pressurized imperfect cylindrical shells,” AIAA Journal, vol. 3, no. 8, pp. 1461–1466, 1965.
[6] H. Crate, S. Batdorf, and G. W. Baab, “The effect of internal pressure on the buckling stress of thin-walled circular cylinders under torsion,” DTIC Document, Tech. Rep., 1944.
[7] A. Robertson, H. Li, and D. Mackenzie, “Plastic collapse of pipe bends under combined internal pressure and in-plane bending,” International Journal of Pressure Vessels and Piping, vol. 82, no. 5, pp. 407–416, 2005.
[8] H. Yudo and T. Yoshikawa, “Buckling phenomenon for straight and curved pipe under pure bending,” Journal of Marine Science and Technology, 2014.
[9] V. Polenta, S. Garvey, D. Chronopoulos, A. Long, and H. Morvan, “Optimal internal pressurisation of cylindrical shells for maximising their critical bending load,” Thin-Walled Structures, vol. 87, pp. 133–138, 2015.
[10] H. M. Mourad and M. Y. Younan, “Limit-load analysis of pipe bends under out-of-plane moment loading and internal pressure,” Journal of pressure vessel technology, vol. 124, no. 1, pp. 32–37, 2002.
[11] A. Hilberink, Mechanical behaviour of lined pipe. Ph. D. Thesis, Delft Technical University, ISBN 978-94-6186-012-5, 2011.
[12] C. Thinvongpituk and S. Poonaya, “A study of the ovalisation of circular tubes subjected to pure bending,” in Current Themes in Engineering Science 2008: Selected Presentations at the World Congress on Engineering2008, vol. 1138, no. 1. AIP Publishing, 2009, pp. 129–140.