Equivalent Model for Interlocked Carcass Under Axial Loads

Abstract

The modelling of flexible pipe interlocked carcasses is complicated when considering all the geometric complexity of their profile. A possible approach is to model them as cylindrical equivalent layers. To follow this path several alternatives can be considered in changing the geometrical and material properties. However, the thickness and the mean radius of those layers must not be changed to not interfere with the diameter of the other flexible pipe layers. In this paper, a model of an orthotropic cylindrical layer, with the same thickness and mean diameter of the original carcass layer is constructed and its material parameters are adjusted for axial loads using a finite element model of the real carcass profile.

A review on predicting critical collapse pressure of flexible risers for ultra-deep oil and gas production

“…By assuming that both the shell and the carcass have the same stiffness (membrane, bending and torsion), they determined the equivalent properties of that orthotropic shell. This method is often used to study the responses of carcass layer subjected to axial loads [37][38][39] or crush [3,[40][41][42] due to the orthotropic mechanical properties of the equivalent shell. Since the carcass layer, however, withstands radial loads, mostly, the treatment of helical carcass wire as a homogeneous ring by discarding its lay angle in collapse studies is more ac- .…”