Effect of Ring Support Position and Geometrical Dimension on the Free Vibration of Ring-Stiffened Cylindrical Shells

2014 ◽  
Vol 580-583 ◽  
pp. 2879-2882
Author(s):  
Xiao Wan Liu ◽  
Bin Liang
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Shell Theory ◽  
Cylindrical Shells ◽  
Ritz Method ◽  
Geometrical Dimension ◽  
Stiffened Cylindrical Shell ◽  
Simply Supported ◽  
Ring Support ◽  
Stiffened Cylindrical Shells

Effect of ring support position and geometrical dimension on the free vibration of ring-stiffened cylindrical shells is studied in this paper. The study is carried out by using Sanders shell theory. Based on the Rayleigh-Ritz method, the shell eigenvalue governing equation is derived. The present analysis is validated by comparing results with those in the literature. The vibration characteristics are obtained investigating two different boundary conditions with simply supported-simply supported and clamped-free as the examples. Key Words: Ring-stiffened cylindrical shell; Free vibration; Rayleigh-Ritz method.

The Transient Response of Imperfect Thin-Walled Stiffened Cylindrical Shell Exposed to Side-On Underwater Explosion

2009 ◽  
Author(s):  
Ching-Yu Hsu ◽  
Chan-Yung Jen
Keyword(s):  
Cylindrical Shell ◽  
Transient Response ◽  
Cylindrical Shells ◽  
Underwater Explosion ◽  
Stiffened Cylindrical Shell ◽  
Analysis And Design ◽  
Finite Element Software ◽  
Pressure Load ◽  
Thin Walled ◽  
Stiffened Cylindrical Shells

The thin-walled stiffened cylindrical shells are usually applied in a submarine which takes the external pressure load, or in a boiler, pressure vessel or pipeline system which takes the internal pressure load. The thin-walled stiffened cylindrical shells under hydrodynamic loading are very sensitive to geometrical imperfections. This study is investigating an imperfect thin-walled stiffened cylindrical shell (out-of-round ratio is ψ = 2%) at a depth of 50m below the water level to see how it withstands sideward TNT 782 kg underwater explosion loading so as to understand its structural transient response. ABAQUS finite element software is used as an analysis tool in the current study, meanwhile, during the analysis process, the Fluid-Structure Interaction (FSI) condition is employed. The structural transient response results of stress and displacement time history of the imperfect thin-walled stiffened cylindrical shell can be used as a reference for the anti-underwater explosion analysis and design of future submersible vehicles, pressure hulls or related structural designs.

Free Vibrations of Longitudinally Stiffened Cylindrical Shells

1974 ◽  
Vol 41 (4) ◽  
pp. 1087-1093 ◽  
Author(s):  
J. T. S. Wang ◽  
S. A. Rinehart
Keyword(s):  
Experimental Data ◽  
Free Vibration ◽  
Cylindrical Shells ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Structural System ◽  
Isotropic Cylinder ◽  
Simply Supported ◽  
Thin Walled ◽  
Stiffened Cylindrical Shells

This study is concerned with the free-vibration characteristics of thin cylindrical shells reinforced by longitudinal stringers for any edge boundary conditions. The structural system is treated as an isotropic cylinder interacting with a set of discrete thin-walled stringers. Frequencies of simply supported shells obtained according to the present analysis compare favorably with Ritz solution and existing experimental data. For mode shapes, the present analysis often yields much better results than Ritz solution. Numerical results for frequencies and mode shapes for clamped-clamped cylindrical shells are included, and frequencies of a shell with very flexible stiffeners compare favorably with frequencies of an unstiffened shell.

Vibration Analysis for Rotating Ring-Stiffened Cylindrical Shells With Arbitrary Boundary Conditions

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Lun Liu ◽  
Dengqing Cao ◽  
Shupeng Sun
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Vibration Analysis ◽  
Cylindrical Shells ◽  
Ritz Method ◽  
Free Vibration Analysis ◽  
Arbitrary Boundary ◽  
Arbitrary Boundary Conditions ◽  
Classical Boundary ◽  
Stiffened Cylindrical Shells

The free vibration analysis of rotating ring-stiffened cylindrical shells with arbitrary boundary conditions is investigated by employing the Rayleigh–Ritz method. Six sets of characteristic orthogonal polynomials satisfying six classical boundary conditions are constructed directly by employing Gram–Schmidt procedure and then are employed to represent the general formulations for the displacements in any axial mode of free vibrations for shells. Employing those formulations during the Rayleigh–Ritz procedure and based on Sanders' shell theory, the eigenvalue equations related to rotating ring-stiffened cylindrical shells with various classical boundary conditions have been derived. To simulate more general boundaries, the concept of artificial springs is employed and the eigenvalue equations related to free vibration of shells under elastic boundary conditions are derived. By adjusting the stiffness of artificial springs, those equations can be used to investigate the vibrational characteristics of shells with arbitrary boundaries. By comparing with the available analytical results for the ring-stiffened cylindrical shells and the rotating shell without stiffeners, the method proposed in this paper is verified. Strong convergence is also observed from convergence study. Further, the effects of parameters, such as the stiffness of artificial springs, the rotating speed of the ring-stiffened shell, the number of ring stiffeners and the depth to width ratio of ring stiffeners, on the natural frequencies are studied.

Local loads on a toroidal shell

1992 ◽  
Vol 27 (2) ◽  
pp. 59-66 ◽  
Author(s):  
D Redekop ◽  
F Zhang
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Elastic Shell ◽  
Toroidal Shell ◽  
Pipe Bend ◽  
Local Loads ◽  
Simply Supported ◽  
Linear Elastic ◽  
Wide Range ◽  
Theory Solution

In this study the effect of local loads applied on a sectorial toroidal shell (pipe bend) is considered. A linear elastic shell theory solution for local loads is first outlined. The solution corresponds to the case of a shell simply supported at the two ends. Detailed displacement and stress results are then given for a specific shell with loadings centred at three positions; the crown circles, the extrados, and the intrados. These results are compared with results for a corresponding cylindrical shell. The paper concludes with a table summarizing results for characteristic displacements and stresses in a number of shells, covering a wide range of geometric parameters.

Laminated Composite Stiffened Cylindrical Shell Panels with Cutouts under Free Vibration

2015 ◽  
Vol 5 (3) ◽  
pp. 37-63 ◽  
Author(s):  
Sarmila Sahoo
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Laminated Composite ◽  
Beam Element ◽  
Benchmark Problems ◽  
Finite Element Code ◽  
Optimum Size ◽  
Isoparametric Element ◽  
Stiffened Cylindrical Shell ◽  
Practical Constraints

The free vibration of laminated composite stiffened cylindrical shell panels in the presence of cutout is investigated. A finite element code is developed using eight-noded curved quadratic isoparametric element for shell with a three noded beam element for stiffener and the formulation is validated through solution of benchmark problems which were earlier solved by other researchers. Parametric study is carried out varying the size of the cutouts and their positions with respect to the shell centre for different edge constraints. The results are presented in the form of figures and tables. The results are further analyzed to suggest guidelines to select optimum size and position of the cutout with respect to shell centre considering the different practical constraints.

Free vibration analysis of porous laminated rotating circular cylindrical shells

2019 ◽  
Vol 25 (18) ◽  
pp. 2494-2508 ◽  
Author(s):  
Ahmad Reza Ghasemi ◽  
Mohammad Meskini
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Cylindrical Shells ◽  
Free Vibration Analysis ◽  
Equilibrium Equations ◽  
Rotating Speed ◽  
Simply Supported ◽  
Numerical Result ◽  
Love’S Shell Theory ◽  
Circular Cylindrical Shells

In this research, investigations are presented of the free vibration of porous laminated rotating circular cylindrical shells based on Love’s shell theory with simply supported boundary conditions. The equilibrium equations for circular cylindrical shells are obtained using Hamilton’s principle. Also, Navier’s solution is used to solve the equations of the cylindrical shell due to the simply supported boundary conditions. The results are compared with previous results of other researchers. The numerical result of this study indicates that with increase of the porosity coefficient the nondimensional backward and forward frequency decreased. Then the results of the free vibration of rotating cylindrical shells are presented in terms of the effects of porous coefficients, porous type, length to radius ratio, rotating speed, and axial and circumferential wave numbers.

scholarly journals Wave Based Method for Free Vibration Analysis of Ring Stiffened Cylindrical Shell with Intermediate Large Frame Ribs

2013 ◽  
Vol 20 (3) ◽  
pp. 459-479 ◽  
Author(s):  
Meixia Chen ◽  
Jianhui Wei ◽  
Kun Xie ◽  
Naiqi Deng ◽  
Guoxiang Hou
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Structure Type ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Arbitrary Boundary ◽  
Stiffened Cylindrical Shell

Wave based method which can be recognized as a semi-analytical and semi-numerical method is presented to analyze the free vibration characteristics of ring stiffened cylindrical shell with intermediate large frame ribs for arbitrary boundary conditions. According to the structure type and the positions of discontinuities, the model is divided into different substructures whose vibration field is expanded by wave functions which are exactly analytical solutions to the governing equations of the motions of corresponding structure type. Boundary conditions and continuity equations between different substructures are used to form the final matrix to be solved. Natural frequencies and vibration mode shapes are calculated by wave based method and the results show good agreement with finite element method for clamped-clamped, shear diaphragm – shear diaphragm and free-free boundary conditions. Free vibration characteristics of ring stiffened cylindrical shells with intermediate large frame ribs are compared with those with bulkheads and those with all ordinary ribs. Effects of the size, the number and the distribution of intermediate large frame rib are investigated. The frame rib which is large enough is playing a role as bulkhead, which can be considered imposing simply supported and clamped constraints at one end of the cabin and dividing the cylindrical shell into several cabins vibrating separately at their own natural frequencies.

Free Asymmetric Vibrations of Composite Full Circular Cylindrical Shells Stiffened by a Bonded Central Shell Segment

2004 ◽  
Author(s):  
U. Yuceoglu ◽  
V. O¨zerciyes
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Natural Frequencies ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Adhesive Layer ◽  
Shear Stresses ◽  
First Order ◽  
Stress Resultant ◽  
Circular Cylindrical Shells

This study is concerned with the “Free Asymmetric Vibrations of Composite Full Circular Cylindrical Shells Stiffened by a Bonded Central Shell Segment.” The base shell is made of an orthotropic “full” circular cylindrical shell reinforced and/or stiffened by an adhesively bonded dissimilar, orthotropic “full” circular cylindrical shell segment. The stiffening shell segment is located at the mid-center of the composite system. The theoretical analysis is based on the “Timoshenko-Mindlin-(and Reissner) Shell Theory” which is a “First Order Shear Deformation Shell Theory (FSDST).” Thus, in both “base (or lower) shell” and in the “upper shell” segment, the transverse shear deformations and the extensional, translational and the rotary moments of inertia are taken into account in the formulation. In the very thin and linearly elastic adhesive layer, the transverse normal and shear stresses are accounted for. The sets of the dynamic equations, stress-resultant-displacement equations for both shells and the in-between adhesive layer are combined and manipulated and are finally reduced into a ”Governing System of the First Order Ordinary Differential Equations” in the “state-vector” form. This system is integrated by the “Modified Transfer Matrix Method (with Chebyshev Polynomials).” Some asymmetric mode shapes and the corresponding natural frequencies showing the effect of the “hard” and the “soft” adhesive cases are presented. Also, the parametric study of the “overlap length” (or the bonded joint length) on the natural frequencies in several modes is considered and plotted.

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