Document Type : Research Paper

Authors

1 mechanical engineering department, faculty of engineering, university of Kurdistan,

2 civil engineering department, faculty of engineering, university of kurdistan, sanandaj, iran

Abstract

Water storage tanks are amongst the essential infrastructures, and the study of their natural frequencies plays a pivotal role in predicting and detecting dynamic behavior. Therefore, it helps to the uninterrupted operation of an industrial plant and the use of tank water in emergencies. This paper has studied the influence of different shell materials including steel, aluminum, and laminated composites with three types of different fiber orientations, on the natural frequencies of thin-walled aboveground water storage tanks that have pinned boundary conditions at the base. Models investigated in this paper, either the roof is without an internal support structure or else a group of columns and radial beams are used for supporting it. These huge tanks had the height to diameter ratio 0.4, and a water surface at 90% of the height of the tank's cylinder. The thicknesses of the cylindrical shells are tapered. The tanks without internal support included the vibrations that affect the cylinder mode shapes or the roof mode shapes or simultaneously both the cylinder and roof mode shapes. On the other hand, the mode shapes of the tanks with internal support affect predominantly only the cylinder. Among the studied tanks, the third type of composite tanks had the highest rigidity, and the first type of composite tanks had the lowest rigidity. The natural frequencies related to the first modes of vibrations for cylinder and roof shells with a wide range of circumferential wave numbers (n) and an axial half-wave (m) are studied.

Graphical Abstract

Influence of Material and Internal Support on the Natural Frequencies of Thin-Walled Cylindrical Tanks

Keywords

Main Subjects

[5] Haroun MA, Tayel MA, "Asymmetrical vibrations of tanks-analytical", Journal of Engineering Mechanics, Vol. 111, No.3, pp. 346-358, (1985).
[26] Simulia DC, "Abaqus Analysis User's Manual, Dassault Syst", Pawtucket, USA, (2016).
[27] Jack RV, "the behavior of shells composed of isotropic and composite materials", Kluwer Academic Publishers, Boston, (1993).
[28] Eurocode 8, "Design of Structures for Earthquake Resistance, Part 4: Silos, Tanks and Pipelines (BS EN 1998-4:2006)", European Committee for Standardization, Brussels, (2006).    
[29] IITK-GSDMA, "Guidelines for Seismic Design of Liquid Storage Tanks", Gujarat State Disaster Management Authority Gandh inagar, Kanpur, India, (2007).
[30] "Seismic design of storage tanks", New Zealand Society for Earthquake Engineering (NZSEE) Inc, Wellington, New Zealand, (2009).
[32] Williston LW, Haroun MA, Proceedings of Fourth US National Conference on Earthquake Engineering, Palm Springs, CA, "Comparison of available analytical options for cylindrical storage tank response subjected to ground motion", Vol.3, pp. 207-216, (1990).
CAPTCHA Image