Helical buckling of a tube in an inclined wellbore

In this paper, helical buckling of an elastic tube in an inclined well bore under the action of its own weight and a compressive force applied at its upper end is studied. The tube is considered to be supported by hinges with the upper end free to rotate with respect to its axis. It can also move fr eely in the axial direction. The tube buckles initially with a sinusoidal m ode. In the post-buckling state, the shape of the tube can evolve to be hel ical. Our interest is to find the critical force for helix formation. In th is study, the buckling force for helix formation is expressed as a Rayleigh 's quotient, and then solved by Rayleigh's principle using the Rayleigh-Rit z technique. (C) 2000 Elsevier Science Ltd. All rights reserved.