Simplified Approaches to Modeling of Lateral Wire Buckling in the Tensile Armour of Flexible Pipes

Abstract

In the present paper, simplifications of methods developed for modeling of lateral wire buckling in the tensile armour layers of flexible pipes are proposed. Lateral wire buckling may occur during pipe laying in ultra-deep waters. In this scenario a flexible pipe is subjected to repeated bending and axial compression due to hydrostatic pressure on the end cap of an empty pipe. If the outer sheath is breached, these loads may cause wire slippage towards states in which the load carrying ability is reduced and wire buckling in the circumferential pipe direction occurs. This leads to characteristic deformation patterns, which may compromise the structural integrity of the entire pipe structure. On the other hand, these loads may cause overstressing of the wires, if the outer sheath is intact. Simplifications of established models for calculation of the load carrying ability are in the present context proposed in a manner, by which the effect of adjacent pipe layers on the postbuckled response can be estimated. The simplifications enables significant reduction of the computational time, which is necessary to calculate the load carrying ability of a given pipe structure.