Numerical sensitivity analysis of corroded pipes and burst pressure prediction using finite element modeling

Abstract

Accurately predicting the failure pressure for corroded pipes transmitting natural resources such as oil and gas is crucial to prevent catastrophic failure and save costs. Several parameters affect the pipe's burst pressure, precisely the defective width, which is essential yet under debate. In this study, parameters such as the corrosion depth (25%, 50%, and 75%), angle (10⁰, 15⁰, 45⁰ and 90⁰), and length-to-diameter ratio “Lc/D" (0.25, 0.5, 1 and 1.5), were numerically investigated through sensitivity analysis, besides the pipes' size “D/t" ratio (16.19, 23.67, 42.64 and 79.79). The study also explored the adequacy of the previous burst pressure predicting models and proposed a new model through FE modeling. The results revealed that defect level significantly reduced the burst pressure regardless of defect angle, length, and pipe size. The defect angle ranges from 10⁰ to 45⁰, and the Lc/D ratio is less than 1, significantly impacting the burst pressure reduction for shallow and deep defects (25% and 75% wall loss). However, this impact disappears at the Lc/D ratio equals one. The findings showed that the old predictions, ASME B31G and RSTRENG, were more conservative than the newer models, DNV and Leis, for shallow defects and non-conservative for deep defects with intermediate lengths. The models that considered the material's strain hardening, such as Shaui, Leis, Ma, phan, and Netto, enhanced the predictions compared to the old ones, especially at extended corrosion. Finally, the design charts through the proposed model were generated for further adoption by codes.