Stability Analysis Of Cylindrical Shells Research Articles

Nonlinear stability of ES-FG porous sandwich cylindrical shells subjected to axial compression in thermal environment

Stability analysis of cylindrical shells subjected to axial compression is a common problem in engineering applications. The phenomenon of instability can easily appear with thin cylindrical shells. Therefore, to increase the load-carrying capacity of this type of structure, the cylinders are increased in thickness by adding a porous core layer and reinforcing orthogonal stiffeners. In this study, the nonlinear buckling and postbuckling behavior of functionally graded (FG) porous sandwich cylindrical shells with orthogonal eccentrically stiffeners (ES) are investigated via analytical approach. The FG porous sandwich cylindrical shells are rested on Pasternak elastic foundations and subjected to axial compression load in a thermal environment. The reinforcement of the shells is achieved through closely spaced stringers and rings, with the material properties of both the shell and stiffeners graded continuously in the thickness direction. The governing equations are derived based on the Donnell’s shell theory with von Karman geometrical nonlinearity and the smeared stiffeners technique. The Galerkin procedure is employed to ascertain the critical load and post-buckling response, employing a three-term deflection solution. The study analyzed the effects of parameters such as porosity coefficient, material, temperature, dimensional parameters, stiffener, and foundation characteristics.

Stability analysis of cylindrical shells containing a fluid with axial and circumferential velocity components

The stability of an elastic circular cylindrical shell of revolution interacting with a compressible liquid (gas) flow having both axial and tangential components is analyzed. The behavior of the fluid is studied within the framework of potential theory. The elastic shell is described in terms of the classical theory of shells. Numerical solution of the problem is performed using a semianalytical finite element method. Results of numerical experiments for shells with different boundary conditions and geometric dimensions are presented. The effects of fluid rotation on the critical flow velocity and the effect of axial fluid flow on the critical angular velocity of fluid rotation were estimated.

On stability of cylindrical shells of variable thickness with initial imperfections

The paper outlines a numerical method for stability analysis of cylindrical shells with initial imperfections. We solve a nonlinear buckling problem for a cylindrical shell with variable wall thickness under surface pressure. The imperfections of the shell are modeled as the first buckling mode. A probabilistic approach is used to determine the reliability against buckling of the cylindrical shell with the probability density of initial imperfections represented by uniform distribution, triangular distribution, or Gaussian distribution

Stability of Laminated Shells Made of Materials with one Plane of Elastic Symmetry

The paper sets forth a technique, based on the Kirchhoff–Love theory of shells, for solving stability problems for thin-walled laminated shells of revolution made of an anisotropic material with one plane of elastic symmetry. The resolving system of differential equations is of the 16th order since the symmetric and asymmetric buckling modes are coupled. The results from a stability analysis of cylindrical shells made of carbon plastics and subjected to compression are analyzed against the angle of the principal directions of elasticity. The influence of boundary conditions is studied. The error due to neglecting the coupling of buckling modes is estimated

Stability of Cylindrical Shells with High Ribs

The paper presents a technique for stability analysis of cylindrical shells reinforced with longitudinal elements in the form of a plate or a flanged plate. The effect of the widths of the plate and flange on the critical stress and buckling modes is analyzed

Stability analysis of cylindrical shells subjected to complex loads

The paper deals with stability analysis of shell on the basis FEM via Castem 2000. The numerical results of stability problems of cylinders subjected to different loads as compress load, pressure, concentrated and combined loads are compared with analytical result and give a good agreement. The influence of changing radius of the cylindrical shell on the unstable forms and the influence of angles of fibers on unstable behaviour of laminated composite shell are considered. Numerical results and corresponding programs by languages Gibian given in the paper to realize software Castem 2000 can be applied in the design and in the stability analysis of the shell with more complex conditions

Stability analysis of cylindrical shells using refined non‐conforming rectangular cylindrical shell elements

AbstractThe accuracy of stability analysis depends on the accuracy of both the element stiffness matrix and geometry stiffness matrix. Therefore, when carrying out the stability analysis of thin cylindrical shells using the finite element methods will require, firstly, a refined non‐conforming rectangular curved cylindrical shell element RCSR4 is proposed according to the refined non‐conforming FE method, in which both the C1 and C0 weak continuity conditions are satisfied and as a result, can ensure the convergence of computation. At the same time, a refined geometrical stiffness matrix is introduced to replace the standard consistent geometrical stiffness matrix. Simple expressions of the refined constant strain matrices with adjustable constants are introduced with respect to the weak continuity conditions. Numerical examples are presented to show that the present method can indeed improve the performance and the accuracy in stability analysis. Copyright © 2001 John Wiley & Sons, Ltd.

Stability of orthotropic corrugated cylindrical shells

A technique for stability analysis of cylindrical shells with a corrugated midsurface is proposed. The wave crests are directed along the generatrix. The relations of shell theory include terms of higher order of smallness than those in the Mushtari–Donnell–Vlasov theory. The problem is solved using a variational equation. The Lame parameter and curvature radius are variable and approximated by a discrete Fourier transform. The critical load and buckling mode are determined in solving an infinite system of equations for the coefficients of expansion of the resolving functions into trigonometric series. The solution accuracy increases owing to the presence of an aggregate of independent subsystems. Singularities in the buckling modes of corrugated shells corresponding to the minimum critical loads are determined. The basic, practically important conclusion is that both isotropic and orthotropic shells with sinusoidal corrugation are efficient only when their length, which depends on the waveformation parameters and the geometric and mechanical characteristics, is small

Effects of elastic foundation on the dynamic stability of cylindrical shells

A formulation for the dynamic stability analysis of cylindrical shells resting on elastic foundations is presented. In this previously not studied problem, a normal-mode expansion of the partial differential equations of motion, which includes the effects of the foundation as well as a harmonic axial loading, yields a system of Mathieu-Hill equations the stability of which is analyzed using Bolotin's method. The present study examines the effects of the elastic foundation on the instability regions of the cylindrical shell for the transverse, longitudinal and circumferential modes.

Linear and nonlinear stability analysis of cylindrical shells

The paper describes the application of a curved isoparametric shell element to large displacement analyses including instability phenomena. A total Lagrangian formulation has been adopted using the standard incremental/iterative solution procedure. The linear stability analyses usually performed for the initial position were repeated at several advanced fundamental states on the nonlinear prebuckling path. Thus a current estimate of the final failure load is given. The method has been applied to several perfect and imperfect cylindrical shells under uniform pressure or wind load. Finally the example of a cylindrical panel under one concentrated transverse load is discussed.

Stability analysis of cylindrical shells under nonaxisymmetric pressure

Stability analysis of cylindrical shells under nonaxisymmetric pressure

Linearized characteristics method for supersonic flow past vibratingshells.

A linearized characteristics method is developed for the aeroelastic stability analysis of cylindrical shells in supersonic flow. This procedure permits a rapid numerical solution of the complete unsteady linearized potential equation for arbitrarily prescribed axial deflection modes, reduced frequency, circumferential mode number, and cylinder length-to-radius ratio. The generalized aerodynamic forces calculated by the present aerodynamic theory are in excellent agreement with a previous Laplace-transform solution by Dowell and Widnall.

A method of stability analysis of cylindrical shells under biaxial compression

The paper applies the method of generalized power series to the analysis of stability of circular cylindrical shells under combined radial pressure and axial force. The numbers of halfwavelengths appearing in original formulas are eliminated using the condition of minimum loading, and effective formulas are derived, expressing the critical loadings in terms of material constants and the geometry of the shell only. Hydrostatic pressure is analyzed as a particular case. Inversion of series makes it possible to obtain direct formulas for the necessary wall thickness if the loadings are given. Separation lines between moderate-length and long shells and between the ranges of elastic and inelastic buckling are discussed in detail. The proposed procedure may be applied to other types of loading as well. Nomenclature E = Young's modulus P = axial force (compressive), referred to unit length of the perimeter R = mean radius of the shell S = intensity of loading U = ra2, number of circumferenti al half-waveleng ths squared V = n2, number of axial half-wavelengths squared V = value of V corresponding to one axial half-wavelength h = thickness of the shell I = length of the shell m = number of circumferenti al half-waveleng ths at the length of half-perimete r n = number of axial half-wavelengths at the length of halfperimeter p = radial external pressure q = dimensionless intensity of loading a = parameter determining the contribution of individual loadings X = transversal slenderness of the shell, proportional to R/h v = Poisson's ratio ap = proportional limit of the material at uniaxial compression