Stress/strain state investigations for extreme points of thin wall cylindrical tanks

Abstract

In all branches of industry, especially in power-engineering, thin wall steel structures are extensively used. Land vertical cylindrical tanks are examples of such structures. The manufacture and assembling of these structures are usually accompanied by deviations from an ideal cylindrical form. Therefore, the exact evaluation of real local imperfections and common deviations from the analytical model of the tank is very important for such potentially dangerous structures. The main objective of the presented investigations is to identify stress/strain state of the wall tank with local imperfections from the ideal cylindrical surface, taking into account the membrane theory of the shells by using the analytical method, natural experiment and the finite element method. Besides, across the tank wall at the sites of its rigidity variation, rigidity ribs and at places of the load’s significant change, total moment internal forces and stresses arise, which are defined by a solution of the problem of the beam on the elastic ground. The given investigation also suggests the solution of the above-mentioned problem not only for the case when the tank wall is considered as a (long) flexible shell but as a semi-rigid one, when the edge effect is distributed over the whole wall’s height.