An Empirical Equation for Failure Pressure Prediction of High Toughness Pipeline with Interacting Corrosion Defects Subjected to Combined Loadings Based on Artificial Neural Network

Suria Devi Vijaya Kumar,Mark Ovinis,Saravanan Karuppanan

doi:10.3390/math9202582

Abstract

Conventional pipeline corrosion assessment methods for failure pressure prediction do not account for interacting defects subjected to internal pressure and axial compressive stress. In any case, the failure pressure predictions are conservative. As such, numerical methods are required. This paper proposes an alternative to the computationally expensive numerical methods, specifically an empirical equation based on Finite Element Analysis (FEA). FEA was conducted to generate training data for an ANN after validating the method against full scale burst test results from past research. An ANN with four inputs and one output was developed. The equation was developed based on the weights and biases of an ANN model trained with failure pressure from the FEA of a high toughness pipeline for various defect spacings, defect depths, defect lengths, and axial compressive stresses. The proposed model was validated against actual burst test results for high toughness materials, with a R2 value of 0.99. Extensive parametric study was subsequently conducted to determine the effects of defect spacing, defect length, defect depth, and axial compressive stress on the failure pressure of the pipe. The results of the empirical equation are comparable to the results from numerical methods for the pipes and loadings considered in this study.

Highlights

This study aims to establish a correlation between defect geometries and failure pressure of high toughness corroded pipelines and develop an empirical corrosion assessment method for the failure prediction of high toughness corroded pipelines subjected to internal pressure and axial compressive stress
It can be concluded that the validation of the method for corroded pipes subjected to both internal pressure and axial compressive stress is not as comprehensive as the validation of the method for the assessment of corroded pipes subjected to internal pressure only [15]
An empirical equation for failure pressure prediction of corroded high toughness pipelines with interacting defects subjected to internal pressure and axial compressive stress was developed

Summary

Introduction

Overview of Pipelines in the Oil and Gas Industry. Pipelines are widely utilized for upstream oil and gas operations for the transportation of hydrocarbon from the reservoir to onshore processing facilities. A pipeline stretches across hundreds of kilometers, operating at high pressures and temperatures. This harsh environment results in pipe wall degradation, known as corrosion [1]. The hoop stress is distributed evenly throughout the pipe. In the presence of corrosion defects, the hoop stress distribution is nonuniform [2,3,4]

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