Numerical modelling of steel pipelines subjected to severe monotonic and cyclic straining

Abstract

Offshore and onshore pipelines may experience extreme loading conditions during their installation and operation, both of monotonic and cyclic nature. Loading actions such as pipeline lateral displacements, tensioning, or external damage by third-party interaction combined with internal or external pressure, may trigger undesirable local or global deformation modes, like section collapse, bulging, wrinkling and denting. Also extreme cycling loading actions involving plastic strain accumulation may result to local or global deformation modes. The available design codes often do not cover such extreme scenarios, so the residual pipe resistance has to be analysed by employing advanced numerical modelling techniques. The paper is focused on the analysis of existing code procedures for strain based design and to their comparison with advanced criteria for monotonic and cyclic loading. Material modelling approaches are proposed to be applied in the numerical analysis. Copyright © 2014 by the International Society of Offshore and Polar Engineers (ISOPE).