Finite Element Modelling of Deepwater UOE Linepipe Manufacturing

Advanced finite element (FE) modelling techniques have been developed for simulation of the UOE linepipe manufacturing process. A through-process modelling approach is adopted using the general purpose FE package ABAQUS, mainly based on 2D plane strain or generalised plane strain assumptions. The FE models developed so far are capable of simulating the UOE pipe forming procedures from plate with machined weld preps, including edge crimping, U-ing, O-ing and pipe expansion (UOE). The FE models also have the ability to simulate the submerged arc welding (SAW) process prior to pipe expansion so that the effect of welding induced residual stresses and strains as well as the weld geometry could be considered adequately in the following FE analysis that is to be performed. Some of the most important aspects of the FE models, such as the prediction of strain distribution, spring back and loading, have been validated against experimental measurements obtained from various plant trials. Extensive parametric studies have been carried out using these FE models to investigate the influence of lubrication on the forming performance, as well as the deformation characteristics of the edge preps in the O-press. The FE modelling techniques are being routinely used to provide practical guidance on tooling design, selection and setting, particularly for the production of smaller diameter and thick-walled linepipes for deep and ultra-deepwater oil and gas applications, where the quality, integrity and consistency of the pipes delivered are critical. Other aspects of the FE modelling exercise relevant to the in-service performance of the pipeline will also be briefly discussed in this paper, including the prediction of residual stress, distortion and ovality, and their affects on pipe collapse resistance.