Stability Of Composite Cylindrical Shells Research Articles

Natural Vibrations and Stability of Composite Cylindrical Shells Containing a Quiescent Fluid

This paper presents the results of investigation of the natural vibrations and stability of circular vertical multilayered cylindrical shells, fully or partially filled with a quiescent compressible fluid subjected to hydrostatic and external static loads. The behavior of the elastic structure and fluid medium is described based on the classical shell theory and Euler’s equations. The linearized equations of motion of the shell, together with the corresponding geometrical and physical relations are reduced to a system of ordinary differential equations with respect to new unknowns. The acoustic wave equation is transformed to a system of differential equations using the method of generalized differential quadrature. The solution of the formulated boundary value problem is developed using Godunov’s orthogonal sweep method. The dependences of the lowest vibration frequencies and critical external pressure on the ply angle and the filling level of two-layer and three-layer cylindrical shells are analyzed in detail. It is demonstrated that, in contrast to the ply angle and a given combination of boundary conditions, the lay-up scheme of composite materials plays different parts in the problems of maximizing the fundamental frequency of vibrations and extending the stability boundaries.

Stability of Composite Cylindrical Shells with Nonclassical Hygrothermal–Electro–Elastic Coupled Loads

An accurate nonlinear hygrothermal-electro-elastic (HTEE) buckling analysis of piezoelectric fiber-reinforced composite cylindrical shells subjected to the coupled loading effects of axial compression and hydrostatic pressure was established by considering the nonuniform prebuckling effect. Nonlinear governing equations were derived based on higher-order shear deformation theory and Novozhilov’s nonlinear shell theory. Accurate critical buckling stresses and pressures and explicit buckling modes for both axisymmetric and nonaxisymmetric buckling were obtained by the Galerkin method. A comparison between the new prediction and existing results is presented and excellent agreement is reported. A comprehensive parametric study of geometric parameters, end conditions, distribution patterns, and hygrothermal-electric multiphysical fields on the buckling behavior of HTEE composite cylindrical shell is also analyzed and discussed.

Stability of Composite Cylindrical Shells with Geometrical and Structural Imperfections Under Axial Compression*

Stability of Composite Cylindrical Shells with Geometrical and Structural Imperfections Under Axial Compression*

Stability Analysis of Composite Cylindrical Shell Containing Rotating Fluid

A semi-analytical finite element method is used to analyze the stability of composite cylindrical shells interacting with a rotating fluid inside them. A mathematical formulation of the problem of deformable structure dynamics is based on the variational principle of virtual displacements and classical shell theory. The behavior of an ideal compressible fluid is described within the framework of the potential theory. The validity of the obtained results is supported by comparing them with the known solutions. Numerical experiments were performed for two- and three-layer cross-ply shells made of boron-epoxy resin with different boundary conditions and geometrical dimensions. It is demonstrated that, for the examined configurations, an increase in the fibre angles leads to a significant increase in the critical rotation velocities of the fluid, regardless of the conditions for fixing the edges of a thin-walled structure.

Numerical Simulation of the Process of Loss of Stability of Composite Cylindrical Shells Under Combined Quasi-Static and Dynamic Actions

Based on the applied theory of shells, an energy-consistent resolving system of equations is constructed, and a complex numerical method is developed which, within in the framework of an explicit variational-difference scheme, makes it possible to solve both quasi-static and dynamic problems of nonlinear nonaxisymmetric deformation and buckling of composite cylindrical shells. The quasi-static loading mode is simulated by setting an internal pressure in the form of a linearly increasing function reaching a steady-state value during three periods of vibration of a composite cylindrical shell at the lower form. The critical buckling load is determined by the characteristic kink on the maximum deflection–loading amplitude curve. The reliability of the method developed is substantiated by comparing calculation results with experimental data. The characteristic forms and critical buckling loads of GRP cylindrical shells as functions of the level of preloading by a quasi-static internal pressure and of the subsequent dynamic loading by an external pressure are analyzed for various reinforcement patterns in a wide range of loading rate.

Stability of Filament-Wound Composite Cylinders Subjected to Hydrostatic Pressure

In order to know the mechanical properties of filament-wound composite cylindrical shells subjected to hydrostatic pressure, solve the buckling problem of pressure hull in deep sea and provide reference for engineering design, it is necessary to research the stability of filament-wound composite cylindrical shells. Based on the theory of thin shells, the governing equations were derived. Stability of composite cylindrical shells was researched by employing Galerkin method to solve the eigenvalue equation. The critical buckling pressure was calculated for cross filament-wound, metal-filament-wound and angle filament-wound composite cylinders under hydrostatic pressure. Compared to the test results, the numerical solution was illustrated to be feasibility. On this basis, the numerical method was interacted with genetic algorithm to search optimum stacking sequence and filament winding angle. Three types of winding pattern [(±θ)12], [(±θ1)x/(±θ2)12-x] and [(±θ1)4/(±θ2)4/(±θ3)4] were investigated, . Further, the effects of winding angle and the corresponding layer number on the critical buckling pressure were evaluated. It was shown that winding angle variation affected the critical buckling pressure significantly. Stability was greatly improved by numerical optimization, and the maximum critical buckling loads are increased by 31.31%, 43.25% and 57.51% compared with the base line, respectively. As the number of design variable increased, the carrying capacity was improved markedly. The optimal critical buckling pressure was increased by 57.17%.

Stability of Composite Cylindrical Shells with Added Mass Interacting with the Internal Fluid Flow

The effect of added masses on the quasistatic (divergence) and dynamic (flutter) loss of stability of cylindrical shells interacting with the internal fluid flow is studied. The dependence of the critical velocity of the fluid on the type of attachment of the added masses is analyzed

Influence of initial deflections on the stability of composite cylindrical shells interacting with a fluid flow

Composite cylindrical shells interacting with an internal fluid flow are analyzed for stability. It is assumed that the shells have small initial geometrical imperfections. The effect of axisymmetric and nonaxisymmetric initial deflections on the critical speeds of the fluid, which cause static (divergent) or dynamic (flutter) loss of stability, is studied

Vibration and stability of composite cylindrical shells containing a FG layer subjected to various loads

The vibration and stability analysis is investigated for composite cylindrical shells that composed of ceramic, FGM, and metal layers subjected to various loads. Material properties of FG layer are varied continuously in thickness direction according to a simple power distribution in terms of the ceramic and metal volume fractions. The modified Donnell type stability and compatibility equations are obtained. Applying Galerkin?s method analytic solutions are obtained for the critical parameters. The detailed parametric studies are carried out to study the influences of thickness variations of the FG layer, radius-to-thickness ratio, lengths-to-radius ratio, material composition and material profile index on the critical parameters of three-layered cylindrical shells. Comparing results with those in the literature validates the present analysis.

Stability of Composite Cylindrical Shells with Noncoincident Directions of Layer Reinforcement and Coordinate Lines

The stability problem is solved for cylindrical shells made of a laminated composite whose directions of layer reinforcement are not aligned with coordinate axes of the shell midsurface. Each layer of the composite is modeled by an anisotropic material with one plane of symmetry. The resolving functions of the mixed variant of shell theory are approximated by trigonometric series satisfying boundary conditions. The stability of the shells under axial compression, external pressure, and torsion is investigated. A comparison with calculation data obtained within the framework of an orthotropic body model is carried out. It is shown that this model leads to considerably erroneous critical loads for some structures of the composites.

Theory and comparison of the effect of composite and shape memory alloy stiffeners on stability of composite shells and plates

The effects of composite and shape memory alloy stiffeners on stability of composite cylindrical shells and rectangular plates subjected to a compressive load are compared. The governing equations for reinforced cylindrical shells are developed based on the Love first approximation theory and smeared stiffeners technique. It is shown that composite stiffeners are more efficient in cylindrical shells, while shape memory alloy stiffeners may be preferable in plates or in long shallow shells. It is also proven that shape memory alloy stiffeners increase the upper and lower buckling loads, i.e. the linear buckling load and the minimum postbuckling load-carrying capacity of cylindrical shells modeled as single-degree-of-freedom systems by the same amount.

Stability of composite cylindrical shells in axial compression

Stability of composite cylindrical shells in axial compression

Stability of inhomogeneous anisotropic cylindrical shells containingelastic cores.

The effect of a soft elastic core on the stability of composite cylindrical shells under pressure, axial load, and torsion is treated by linear theory. Numerical results are given for contemporary filament-wound cylinders. The results indicate that the buckling loads increase indefinitely with increasing values of the core parameter. The increment in buckling load corresponding to an increment in the core parameter is largest for buckling by pressure and smallest for buckling by axial compression.

Errata: "Effect of Heterogeneity on the Stability of Composite Cylindrical Shells under Axial Compression''

Errata: "Effect of Heterogeneity on the Stability of Composite Cylindrical Shells under Axial Compression''

Effect of heterogeneity on the stability of composite cylindrical shells under axial compression.

Heterogeneity effect on multilayer composite cylindrical shell stability under axial compression