tailieunhanh - Nonlinear buckling and post-buckling of eccentrically stiffened functionally graded cylindrical shells surrounded by an elastic medium based on the first order shear deformation theory

In this paper, the nonlinear buckling and post-buckling of an eccentrically stiffened cylindrical shell made of functionally graded materials, surrounded by an elastic medium and subjected to mechanical compressive loads and external pressures are investigated by an analytical approach. The cylindrical shells are reinforced by longitudinal and circumferential stiffeners | Volume 35 Number 4 4 Vietnam Journal of Mechanics, VAST, Vol. 35, No. 4 (2013), pp. 285 – 298 NONLINEAR BUCKLING AND POST-BUCKLING OF ECCENTRICALLY STIFFENED FUNCTIONALLY GRADED CYLINDRICAL SHELLS SURROUNDED BY AN ELASTIC MEDIUM BASED ON THE FIRST ORDER SHEAR DEFORMATION THEORY Dao Van Dung∗ , Nguyen Thi Nga Hanoi University of Science, VNU, Vietnam ∗ E-mail: dungdv90@ Abstract. In this paper, the nonlinear buckling and post-buckling of an eccentrically stiffened cylindrical shell made of functionally graded materials, surrounded by an elastic medium and subjected to mechanical compressive loads and external pressures are investigated by an analytical approach. The cylindrical shells are reinforced by longitudinal and circumferential stiffeners. The material properties of cylindrical shells are graded in the thickness direction according to a volume fraction power-law distribution. The nonlinear stability equations for stiffened cylindrical shells are derived by using the first order shear deformation theory and smeared stiffeners technique. Closed-form expressions for determining the buckling load and load-deflection curves are obtained. The effectiveness of stiffeners in enhancing the stability of cylindrical shells is shown. The effects of volume fraction indexes, material properties, geometrical parameters and foundation parameters are analyzed in detail. Keywords: Stiffened cylindrical shells, nonlinear buckling and post-buckling, functionally graded, foundations. 1. INTRODUCTION Functionally graded material (FGM) cylindrical shells in recent years, are extensively used in many modern engineering applications. These structures are usually rested on or placed in a soil medium modelled as an elastic foundation. Thus, their stability analysis is an important problem and has received considerable interest by researchers. Bagherizadeh et al. [1] investigated the mechanical buckling of FGM cylindrical shell surrounded by Pasternak elastic foundation