STRESS CONCENTRATION IN VERTICAL TANK WELD SEAMS

Authors

Boris V. Uspenskiy, A. Podgorny Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi Str., Kharkiv, 61046, Ukraine), e-mail: Uspensky.kubes@gmail.com, ORCID: 0000-0001-6360-7430

Svetlana N. Buganova, JSC “Kazakh Leading Architecture and Civil Engineering Academy” (28, Ryskulbekov Str., Almaty, 050043, Kazakhstan)

Ulanbator S. Suleymenov, M. Auezov South Kazakhstan State University (5, Taukekhan Ave., Shymkent, 5160012, Kazakhstan)

Konstantin V. Avramov, A. Podgorny Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi Str., Kharkiv, 61046, Ukraine), e-mail: kvavramov@gmail.com, ORCID: 0000-0002-8740-693X

Abstract

The article describes a new method for analyzing and predicting the stress concentration coefficient in a rolled vertical tank weld seam under hydrostatic loading. Vertical tanks are widely used for storing petroleum products. The use of roll-to-roll assembly technology is advisable for a quick and inexpensive installation of oil tanks. However, the use of this technology in the installation of large-capacity tanks leads to the need to use thick rolled steel. This leads to the appearance of significant angularities of the weld seams used to fasten steel sheets in a roll. Such angularities are mechanical stress concentrators and can damage the tank. Therefore, the problem of modeling the dependence of stress concentration factors on the geometrical parameters of angularity is relevant and important to ensure both the economic and environmental efficiency of operation of the oil tanks assembled by the roll-to-roll method. The approach described in this article is based on a combination of a numerical experiment and an approximation approach. The stress concentration factor depends on two dimensionless parameters of the dent. Thus, a method of approximation of a two-dimensional problem is described. This method is applied to the data collected by numerous computational experiments using the finite element approach to construct an approximate model of the stress concentration factor. Such a model can be used to predict stress values, as well as tank strength and durability. The change in material properties in the weld seam is not taken into account. Thus, the estimated stress is higher than the real one and represents a majorant estimate. An approximating model of the stress concentration factor was constructed in the area of angularity of the weld seam of a 3,000 m³ complex structure oil tank under hydrostatic loading. The tank consists of four belts made of steel of various thickness. The density of the tank contents is close to that of water. It has been found that stress concentration increases as the distance to the tank bottom becomes smaller. Therefore, when building an approximating model, the results in the most strained region are considered.

Keywords: vertical tank, hydrostatic loading, stress concentrator, weld, roll-to-roll assembly, dent.

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References

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Received 12 July 2018

Published 30 December 2018