American Journal of Mechanical Engineering, 2015, Vol. 3, No. 6, 230-234 Available online at http://pubs.sciepub.com/ajme/3/6/15 © Science and Education Publishing DOI:10.12691/ajme-3-6-15 Static Structural Analysis of Water Tank Pavol Lengvarsky * , Miroslav Pástor, Jozef Bocko Department of Applied Mechanics and Mechanical Engineering, Faculty of Mechanical Engineering, Technical university of Košice, 042 00 Košice, Slovak Republic *Corresponding author: pavol.lengvarsky@tuke.sk Abstract The paper is devoted to the static analysis water tank. Three different thicknesses of walls of the water tank are proposed and the structure is analysed in order to find appropriate stress and deformation states of structure. The maximal stress level was higher than the yield strength of stainless steel used in structure so seven different variants of stiffeners were proposed for improving stability and strength of structure. Keywords: water tank, container, static analysis, finite element method Cite This Article: Pavol Lengvarsky, Miroslav Pástor, and Jozef Bocko, “Static Structural Analysis of Water Tank.” American Journal of Mechanical Engineering, vol. 3, no. 6 (2015): 230-234. doi: 10.12691/ajme-3-6-15. 1. Introduction The tanks are often used for storage and transportation of liquids, mostly for transport or storage of drinking water, industrial water, petrol, dangerous toxic substances, acids, etc. The questions of strength and stability of such structures are very important in order to insure safe operation of those devices [1-10]. In the following we will deal with a water tank designed for transportation on a truck. The structure was modelled according to drawing documentation and demands of producer (Figure 1). The container will be used for transportation of water and accordingly stainless steel is used as a base material of the structure. The maximal length of the water tank is 4533 mm, the width in the top and bottom part of the body is 2422 mm,1005 mm, respectively and the height of structure is 1241 mm. Figure 1. The 3D model of the water tank 2. Theoretical Background Nowadays, the finite element method (FEM) is the most popular and spread method of computation in continuum mechanics. A deformation variant has been expanded in practice. From numerical point of view it is numerical method of approximation of boundary problem. The body (Figure 2) is replaced by union of set of subregions, which we call finite elements [1,3,4,6]. Node Finite element Figure 2. Solution of boundary problem [1] The finite element method can be based e.g on the principle virtual displacements. At the element level we can write equation , T T T V V A dV dV dA δ δ δ = + ∫∫∫ ∫∫∫ ∫∫ εσ uX up (1) where , , , , , , dV dA δ δ εσ uXp is variation of strain vector, stress vector, variation of displacement vector, body force vector, pressure vector, infinitesimal volume and infinitesimal area, respectively [1,3]. Displacement u can be expressed as , ⋅ u=N d (2) where N is matrix containing the shape functions and d is vector of node displacement. Now we have equation , ⋅ ε =Bd (3) which expresses the dependence of the strain vector ε on the node displacement vector d and B is matrix containing derivatives of shape functions. In case of linear elastic material we have relation , ⋅ σ =D ε (4) where D is matrix of elastic constants. Further we use equation (3) and we get