Failure analysis of storage tank F. Trebun ˇa * , F. S ˇ imc ˇa ´k, J. Bocko Department of Applied Mechanics and Mechatronics, Technical University of Kos ˇice, 042 00 Kos ˇice, Slovakia Received 13 December 2007; accepted 27 December 2007 Available online 20 January 2008 Abstract This paper has studied failure of a hot water storage tank. During operation, one of the two tanks has been damaged by collapse of its roof. Consequently, analytical, numerical and experimental analysis of possible failure reasons was per- formed. Extreme stresses in the structure during its operation were determined taking into account shape and geometry imperfections as well as corrosion influence. These values were verified numerically by the finite element method. Extensive experiments performed by strain gauge measurements on the second tank of the same design helped us determine time- dependent stresses in extremely loaded locations during the chosen regimes of operation. The results of analysis allowed us to assess the failure reason and to express the recommendations for further analysis of the non-damaged tank. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Tank failures; Finite element analysis; Stress analysis 1. Introduction Two vertical non-pressure tanks of the same structure (approximately 30 years old) originally designed for heavy oil storage were used as storage tanks for hot water (temperature 65–95 °C). The tanks were recon- structed, equipped with the necessary technological devices and brought into operation (Fig. 1). After two weeks of operation the roof structure of the storage tank collapsed (Fig. 2). The aim of solution is to analyze the loading of the storage tank during its operation, to judge the reasons for its failure and to propose the corrective actions for safely operation of the second tank, which was designed for the same purposes and oper- ation as the first one. 2. Basic facts about the tank and its operation As mentioned above, the aim of the paper is to investigate the vertical cylindrical tank with the spherical roof and basic dimensions as given in Fig. 3: 1350-6307/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.engfailanal.2007.12.005 * Corresponding author. Tel.: +421 55 6022462; fax: +421 55 6334738. E-mail address: frantisek.trebuna@tuke.sk (F. Trebun ˇ a). Available online at www.sciencedirect.com Engineering Failure Analysis 16 (2009) 26–38 www.elsevier.com/locate/engfailanal