In this paper by using the theory of elasto-plastic processes and adjacentequilibrium criterion the governing equations of the elasto-plastic stability problem of conical shells are derived. The Bubnov-Galerkin's method combined with the loading parameter method are applied in solving the mentioned problem. The influence of the hardening characteristics of material on the critical load is investigated. | Vietnam Journal of Mechanics, VAST, Vol. 27, No. 2 (2006), pp. 111 - 119 INFLUENCE OF THE HARDENING CHARACTERISTICS OF MATERIAL ON THE CRITICAL LOAD IN THE ELASTO - PLASTIC STABILITY PROBLEM OF CONICAL SHELLS DAO 1 Huy BrcH 1 AND Vu K HAC BAY 2 Vietnam National University, H anoi 2 University of Forestry A bst ract. In this paper by using the t heory of elasto-plastic processes and adjacentequilibrium criterion the governing equations of the elasto-plastic stability problem of conical shells are derived. The Bubnov-Galerkin's method combined with the loading parameter method are applied in solving the mentioned problem. The influence of the hardening characteristics of material on the critical load is investigated. 1. INTRODUCTION Analysis of the elasto-plastic stability problem of shells with homogeneous membrane stress of the prebuckling state was considered by some authors [1 + 4], but in the case when the prebuckling state is non- homogeneous many difficulties arise in solving the problem, because now stability equations are a set of partial differential equations with variable . coefficients. Otherwise we can get more difficulties in determination of material funct ions occured in the constitutive relations, for example the secant modulus and tangent modulus which become functions of point coordinates. Furthermore in the shell occur elastic and plastic zones, the boundary of which is unknown, it must be determined simultaneously in the solution process. In t his paper the governing equations of the elasto-plastic stability problem of conical shells are developed based on the theory of elasto-plastic processes and the adjacentequilibrium criterion. The Bubnov-Galerkin's method combined with the loading parameter method can be applied in solving considered problem. A piece-wise linearization procedure of the material function figured in constitutive relations is demonstrated for material with general hardening characteristics and t he influence of this
