Definition of the failure region of the oil tank with wall imperfections in combined loading

Abstract

The stability of an oil reservoir with real imperfections of a wall under the joint action of axial compression and surface pressure is studied using a program complex of finite element analysis. To determine the permissible range of fail-safe operation of the reservoir, irregular imperfections of the middle wall surface are simulated as ratios of the buckling forms with different maximum amplitudes obtained in solving the problem of loss of stability by the Lanczos method. The stability of the shell with real and simulated imperfections of the wall is investigated using the nonlinear static problem by the Newton-Raphson method. Critical ratios of axial compression and surface pressure are determined to ensure overall stability of the reservoir wall. The region of failure on the stability of the oil reservoir with real imperfections is obtained.