Analytical model for tensile armors lateral deflections and buckling in flexible pipes

Abstract

The present paper addresses the mechanical behavior of tensile armor wires in a flexible pipe subjected to bending and longitudinal loads. An analytical model is formulated to evaluate the equilibrium state of a single armor wire on a frictionless torus surface by solving a consistent system of six nonlinear differential equations through the application of a perturbation technique. Cases studies are performed where the armor wire's responses to both tensile and compressive loads are discussed and compared with the results obtained from a numerical program. Under the circumstance of axial compression, two potential lateral buckling modes, global and periodic, are uncovered and their corresponding buckling limits are identified by establishing eigenvalue problems. While the global buckling limits are found conservative compared with the test data available in the literature, good agreements are observed for the estimated buckling limits regarding the periodic buckling mode.