Severity of a Small Wrinkle on Oil and Gas Pipeline with Displacement Control Cyclic Tests

Date of Award

2-23-2023

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

Keywords

Structural engineering

Supervisor

S.Das

Supervisor

N.Zamani-Kashini

Rights

info:eu-repo/semantics/embargoedAccess

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Buried pipelines are considered to be the safest, most reliable, and economic mode of transportation for oil and gas found in northern Canadian region which is far from the place of consumption or refineries. Buried oil and gas pipelines with internal pressure passing through unstable slope and water crossing, subjected to soil movement, landslide, and seismic activity may develop wrinkle defects. Wrinkled pipelines subjected to axial cyclic loadings due to extreme weather condition, freeze-thaw cycle is vulnerable to fatigue failure. Despite extensive research work to evaluate the integrity of buried oil and gas pipelines with various defects, there are limited research data, or guidelines for the assessment and behavior of wrinkle defects subjected to axial cyclic loadings. This research program was initiated to investigate the severity of small wrinkle in buried oil and gas pipe with constant internal pressure subjected to different displacement controlled axial cyclic loading with different wrinkle profile. A total of nine experimental full-scale test were conducted on the structural laboratory of University of Windsor along with finite element analysis (FEA) based numerical approach.

This experimental program also utilized the concept of hysteresis loop energy (HLE) in the assessment of wrinkle defects subjected to axial cyclic loading. The study found that the pipes with larger wrinkled amplitudes are expected to compromise the structural integrity of the buried pipelines. In addition, the study also found that the pipe exposed to higher temperature fluctuation or severe environmental conditions results in a larger cyclic displacement and prone to fatigue failure.

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