Assessment of stress concentration factor at hotspots on non-uniform corroded T-joints under axial loading

Vu Dan  Chinh; Do Thanh  Long; Hà Thi Thu  Nguyên; Dinh Quang  Cuong

doi:10.6180/jase.202409_27(9).0008

Assessment of stress concentration factor at hotspots on non-uniform corroded T-joints under axial loading

Vu Dan ChinhThis email address is being protected from spambots. You need JavaScript enabled to view it., Do Thanh Long, Hà Thi Thu Nguyên, and Dinh Quang Cuong

Faculty of Coastal and Offshore Engineering, Hanoi University of Civil Engineering, 55 Giai phong str., Hai ba trung dist., Hanoi 100 000, Vietnam

Received: April 10, 2023
Accepted: October 12, 2023
Publication Date: December 7, 2023

Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.6180/jase.202409_27(9).0008

After many years of operation, the corrosion phenomenon frequently appears on fixed steel offshore platforms. It changes the concentrated stress in joints, greatly increasing fatigue damage, and hastening structural collapse. This study examines the impact of corrosion at various regions along the chord of the compressive T-joint on the stress concentration factor (SCF) of the chord hotspots. Therefore, the region of influence is split into 15 shells. The impact ratio of the thickness in each shell on the SCF is estimated by using the numerical model in 54 scenarios of different corrosion. Also, a formula for calculating the equivalent thickness of a non-uniformly corroded chord is established using the regression approach. The condition that the SCF based on API employing equivalent thickness is comparable to the actual value of the hotspots on the corroded joint using gathered data is satisfied by this equation. Additionally, 4 scenarios for 2 numerical simulations of T-joints are used to validate the equation, together with surveying data from the White Tiger field. Additionally, using an experiment with compressive T-joints strengthened by doubler plates is used to compare the SCF. These outcomes all provide a good match for the new formula, which can reduce the SCF’s computational time in similar conditions.

Keywords: non-uniform corrosion; tubular T-joint; axial loading; stress concentration factor (SCF); numerical models; equivalent thickness

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