Modeling of Elastoplastic Buckling of a Cylindrical Shell with Initial Shape Imperfections and Elastic Filler under External Pressure

A technique has been developed for the numerical solution of nonlinear problems of deformation and elastoplastic buckling of revolution shells with a filler under combined static and dynamic loadings in a two-dimensional formulation. The stability loss problem of steel cylindrical shells with and without elastic filler under linearly increasing external pressure in flat elastic and elastoplastic formulations is considered. When compressing a hollow cylindrical shell, a non-axisymmetric buckling occurs in the second mode in the circumferential direction. Until the stability of both the elastic and elastoplastic shells is lost, a linear increase in the circumferential force is observed until the pressure reaches a critical value, and then its sharp drop. It is established that for an elastic shell the value of the critical load does not depend on the amplitude of the initial imperfection of form. During elastoplastic deformation, a significant dependence of the critical load (up to 20 %) on the amplitude of the initial imperfection of form in the range from 10(-5) to 10(-2) thickness h was revealed for the first time. Similar patterns hold for shells with elastic aggregate, where the level of critical load is determined by the stiffness of the base.