Stability of reinforced cylindrical shells under combined loading

A new approach to solving buckling problems for ribbed cylindrical shells subject to longitudinal force and pressure is proposed. Results for shells reinforced with stringers and rings are presented     

Some features of the buckling of stringer shells

A technique for stability analysis of stringer shells is proposed. It is used to analyze the minimum critical stresses. The dependence of the dimensionless parameters σ_cr/σ_cl on the number of stringers is plotted. The linear and nonlinear theories of ribbed shells are used to examine the features of how stringer shells lose stability. It is shown that the minimum critical stresses determined using the theory of ribbed shells and a structurally orthotropic model are close within the range of stiffness parameters considered __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 2, pp. 59–64, February 2006.     

Stability of ribbed cylindrical shells with a nonideal shape

A finite-difference method was proposed and used for analysis of critical loads of shells that have initial imperfections of different types, both regular and local. Ribbed shells were analyzed with allowance for the discreteness in the arrangement of the ribs. S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 35, No. 12, pp. 33–39, December, 1999.     

On lower-bound estimates of critical loads for cylindrical shells

The paper proposes a new approach to estimate the lower bounds of critical loads for circular cylindrical shells. These bounds are compared with the ordinary lower bound of critical load under which a shell with initial deflections loses stability. The lower bound produced by the approach is higher than the ordinary bound and can be used in design __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 10, pp. 78–85, October 2006.     

Stability of cylindrical ribbed shells affected by compound loading

Methods of stability analysis for unsupported shells affected by compound loading have been expounded quite thoroughly in the literature [1, 2, 5–7]. In this case both the homogeneous, membrane subcritical state [1, 2, 5] as well as the inhomogeneous moment state [6] are considered. The homogeneous membrane subcritical state assumption [5, 6] is employed in the analysis of ribbed shells. The critical loads are found from equations of mixed-type.Timoshenko Institute of Mechanics, Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 30, No. 1, pp. 33–37, January, 1994.     

Analytic upper-bound estimates for the critical loads of perfect ribbed shells

A new approximate approach is proposed to find upper-bound estimates for the critical loads of ribbed shells. Seventeen cases are considered, and the minimum critical load parameter is determined __________ Translated from Prikladnaya Mekhanika, Vol. 41, No. 12, pp. 74–83, December 2005.     

Effect of localized imperfections on the critical loads of ribbed shells

A numerical approach to the assessment of the critical stresses for imperfect ribbed shells is developed. Initial deflections occupying a part of the shell surface (they are circumferentially bounded) are considered. The couple stresses and nonlinearity of the precritical state are taken into account. Numerical examples are given     

Critical loads of shells with high-modulus reinforcement

The analytical method developed to determine the upper and lower critical stresses is applied to cylindrical shells reinforced with stringers and rings. Buckling modes typical of shells reinforced with discrete ribs are considered. The minimum critical loads are determined and compared with available experimental data. Perfect and imperfect ribbed shells with high-modulus reinforcement are studied. It is proved that the effect of small axisymmetric imperfections in such shells is not so drastic as in isotropic shells. Ribs made of a high-modulus material can enhance the stability of shells by a factor of tens