Investigação analítico-numérica do mecanismo de instabilidade lateral dos arames das armaduras de tração de dutos flexíveis

Abstract

The lateral buckling of the flexible pipes tensile armor wires is a relatively new phenomenon dating from the late 1990’s. Both experimental and theoretical approaches do not seem to reach consensus on: the influence of friction, the modes of buckling, the reason for the discrepancies of the experimental results of field and laboratory, etc. The present work aims at the systematic study of lateral instability through the application of concepts developed by the Elastic Stability Theory, proposed by Koiter in 1945. A finite element is proposed for the representation of the mechanical behavior of tensile armor wires settled on elastic foundations, which has the function of representing the frictional forces and the actions of the pipe surrounding layers. It was tried to shed light on the main incongruities mentioned, as well as to qualify the critical points and their secondary paths. In addition to this numerical research model, it is proposed an analytical formulation, obtained by means of symbolic regression, performed by EUREQA® software, which well represents the influence of friction on the critical loads obtained by the numerical model.