Analysis of the economic efficiency of major repairs of the tank foundation by the displacement method

The article features the application of a method of displacement during major repairs of vertical steel tank bases. Premises on the effectiveness of the application of the displacement method for repairing the bases of vertical steel tanks in comparison with the traditional method of repair are put forward. The comparative characteristics of the displacement method and the traditional method of major repairs of the bases of vertical steel tanks are given. The authors proposed a method of temporary displacement of vertical steel tanks, which is new for Russian practice of major repairs. An algorithm for calculating the cost-effectiveness of repairing the bases of VSTs is developed both by the traditional method and by the displacement method proposed by the authors. Technical solutions are substantiated considering calculating the stress-strain state of tank structures under nonaxisymmetric loading. A model is formed and basic parameters of the economic efficiency evaluation of major repairs of the vertical steel tank base are determined. Evaluation of the economic efficiency of major repair procedures and further maintenance of the repaired tank bases is carried out. A high economic efficiency of the new technological method of displacement is proved in comparison with the traditional method.

On the Nonaxisymmetric Loading of Nonhomogeneous Annular Plates of Variable Thickness

In this paper, the stepped reduction method is used to find general solutions for the nonaxisymmetric bending of arbitrary axisymmetric nonhomogeneous annular plates of variable thickness under an arbitrary nonaxisymmetric temperature field and an arbitrary nonaxisymmetric distributed load. In spite of a large number of steps, eventually only two simultaneous algebraic linear equations with two unknowns have to be solved. As an example, the bending of a circular plate, whose solution is known, is carried out by the proposed approach, and it is shown that results obtained by the proposed method compare well with previous solutions obtained by other methods and hence prove the accuracy of the proposed method.

On the Use of a Path-Independent Line Integral for Axisymmetric Cracks With Nonaxisymmetric Loading

A path-independent line integral JA is derived for axisymmetric cracks under nonaxisymmetric loading conditions. The nonaxisymmetric crack problem is solved by expressing its boundary conditions as the sum of a Fourier series. Contribution on JA from each of the Fourier terms in the nonaxisymmetric problem is shown to be decoupled from each other. Relationships between JA and stress intensity factors are also presented for linear elastic fracture problems. Application of JA to numerical fracture mechanics analysis is demonstrated by considering two example problems: an infinitely long circular bar with a penny-shaped internal crack at its center, and a circumferentially cracked pipe (both are under remote tension, bending, and torsion).