Session: 04-01-01 Flexible Pipes & Umbilicals I

Paper Number: 122906

122906 - Symbolic Regression Equations to Predict the Stress Concentration Factors in Flexible Pipes With Damaged Tensile Armors 

FFlexible pipes are fundamental in various offshore oil and gas exploration applications, working as production, gas injection, gas lift, or water injection lines. However, such structures can be damaged infield, reducing their structural capacity and leading to costs associated with replacements, production loss, or oil leakage. Among the various failure modes of flexible pipes, the rupture of the tensile armors is critical, as these armors withstand the axial loads imposed on the pipe. In this context, this work aims to contribute to evaluating the structural integrity of damaged flexible pipes subjected to tensile loads. Given the limitations of analytical models and the high computational cost of models based on the finite element (FE) method in assessing the structural behavior of damaged flexible pipelines, this work proposes an empirical-analytical model obtained through Symbolic Regression (SR) as an expedited alternative for determining the stresses in the tensile armors of damaged flexible pipes. Firstly, several flexible pipes were analyzed with a previously proposed FE model. In these analyses, one up to half of the tensile armors in their outer layers were considered broken. The stress concentration factors (SCF) in the remaining tensile armors were calculated and, together with nondimensional parameters selected to adequately represent the pipe’s mechanical response, formed a dataset analyzed with an SR tool. Finally, a closed-form equation (SR equation) was obtained and combined with an analytical model, allowing the analysis of other damaged flexible pipes. The proposed equation was verified against the FE model results and experimental tests, showing good agreement.

Presenting Author: José Renato Mendes De Sousa Federal University of Rio de Janeiro

Presenting Author Biography: Dr. Jose Renato Mendes de Sousa is a professor of Offshore Structures at the Federal University of Rio de Janeiro (UFRJ), Brazil, where he also graduated as a Civil Engineer in 1997 and received his DSc in 2005. In addition to teaching, Dr de Sousa is a researcher at the Laboratory of Analysis and Reliability of Offshore Structures from the Federal University of Rio de Janeiro, where he collaborates in several projects associated with the mechanics of offshore structures and, particularly, with the mechanical analysis of flexible pipes. He resides in Rio de Janeiro, and you can reach him at jrenato@laceo.coppe.ufrj.br.

Authors:

José Renato Mendes De Sousa Federal University of Rio de Janeiro
Anderson Cunha Dos Santos Federal University of Rio de Janeiro