Open AccessWelded joints of offshore fixed platforms for the extraction of oil, gas and other minerals on shelf
Author(s) -
I. V. Starokon
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/775/1/012149
Subject(s) - welding , joint (building) , submarine pipeline , stress (linguistics) , offshore oil and gas , bending , ultimate tensile strength , structural engineering , seal (emblem) , stress concentration , engineering , materials science , geotechnical engineering , metallurgy , mechanical engineering , fracture mechanics , art , linguistics , philosophy , visual arts
The world is actively developing offshore mineral deposits (oil, gas, coal, steel and other minerals). Offshore fixed platforms are actively used for offshore production. During operation, these platforms are subject to various impacts (wave, wind, etc.), which leads to the occurrence of alternating stresses. Current AC voltages activate fatigue processes in welded joints. Therefore, the knowledge of the peculiarities of the stress state of the welded joints of offshore platforms is the key to understanding the fatigue processes taking place in them. Nowadays various theories offer different understanding of the stresses acting in a welded joint. For example, the strength theory does not take into account the presence of “hot spots” in the welded joint, assuming a uniform distribution of stresses on the welding seam. The influence of static load on the general picture of the stress state in the welded joint was also investigated. As a result of the carried out researches the location of points with the greatest concentration of pressure, influence of thicknesses, diameters and an angle of interface of connected elements is established. The calculations showed that the sharper the angle of connection of the branch to the main pipe, the lower the value of stress concentration coefficients. Stresses acting in the welded joint also increase in case of increase in the diameter and wall thickness of the offshore platform columns. The analysis of the results of the computer model showed that the greatest contribution to the stress state of the platform is the tensile force and bending moment outside the plane, which indicates that the points with the highest stress concentration will be the points located in the direction of the wave beam.