Comparison of Vibration Characteristics of Stiffened Composite Shallow Circular Cylindrical Shell Panels

2002 ◽  
Author(s):  
V. O¨zerciyes ◽  
U. Yuceoglu
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Circular Cylindrical Shell ◽  
Free Vibrations ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Shallow Cylindrical Shell ◽  
Parametric Studies ◽  
Complete Set ◽  
Hit And Run

The problem of “Free Vibrations Centrally and Non Centrally Stiffened Composite Shallow Cylindrical Shell Panels” are briefly considered and their vibration characteristics are compared, in detail, in terms of their natural frequencies and the corresponding mode shapes. First, the complete set of composite shallow cylindrical shell equations are reduced to a system of first order ordinary differential equations in “state-vector” form. Then, by making use of the “Modified Transfer Matrix Method”, the effects of the position and the width of the stiffening shell strip in the natural frequencies and the mode shapes of the panel system are plotted and compared. Some significant results of parametric studies and also the possibility of some kind of hit-and-run type of optimization are presented.

Free Vibration Analysis of Angle-ply Laminated Shallow Cylindrical Shell with Clamped Edges

2000 ◽  
Vol 123 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Kenji Hosokawa ◽  
Minehiro Murayama ◽  
Toshiyuki Sakata
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Numerical Approach ◽  
Free Vibrations ◽  
Numerical Results ◽  
Mode Shapes ◽  
Shallow Cylindrical Shell ◽  
Plastic Composite ◽  
Vibration Tests

In a previous paper, the authors proposed a numerical approach for analyzing the free vibrations of a laminated FRP (fiber reinforced plastic) composite plate. In the present paper, this approach is modified for application to a symmetrically laminated shallow cylindrical shell having a rectangular planform. First, the natural frequencies of the shell are calculated for discussion of the convergence and accuracy of the solution. Next, the effects of the curvature ratio and stacking sequence on the natural frequencies and mode shapes of the shell are studied. Furthermore, to justify the numerical results, vibration tests of the clamped symmetrically laminated shallow cylindrical shell having a square planform are carried out. These experimental results are found to agree well with the numerical results computed using the measured material properties of the lamina.

Free Vibrations of Composite Shallow Circular Cylindrical Shell Panels With a Bonded Central Stiffening Shell Strip

2001 ◽  
Author(s):  
U. Yuceoglu ◽  
V. Özerciyes
Keyword(s):  
Shallow Shell ◽  
Natural Frequencies ◽  
Circular Cylindrical Shell ◽  
Adhesive Layer ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Order System ◽  
Theoretical Formulation ◽  
First Order ◽  
Stress Resultant

Abstract This study is concerned with the “Free Vibrations of Composite Shallow Circular Cylindrical Shells or Shell Panels with a Central Stiffening Shell Strip”. The upper and lower shell elements of the stiffened composite system are considered as dissimilar, orthotropic shallow shells. The upper relatively narrow stiffening shell strip is centrally located and adhesively bonded to the lower main shell element In the theoretical formulation, a “First Order Shear Deformation Shell Theory (FSDST)” is employed. The complete set of the shallow shell dynamic equations (including the stress resultant-displacement and the constitutive equations) and the equations of the thin flexible, adhesive layer are first reduced to a set of first order system of ordinary differential equations. This final set forms the governing equations of the problem. Then, they are integrated by means of the “Modified Transfer Matrix Method”. In the adhesive layer, the “hard” and the “soft” adhesive effects are considered. It was found that the material characteristics of the adhesive layer influence the mode shapes and the corresponding natural frequencies of the composite shallow shell panel system. Additionally, some parametric studies on the natural frequencies are presented.

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.

Vibration Analysis of a Railway Carbody Model as a Non-Circular Cylindrical Shell

2007 ◽  
Author(s):  
Yukinori Kobayashi ◽  
Kotaro Ishiguri ◽  
Takahiro Tomioka ◽  
Yohei Hoshino
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Circular Cylindrical Shell ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Elastic Vibration ◽  
Mode Shapes ◽  
Simply Supported ◽  
Vibration Problems ◽  
Good Agreement

Railway carbody is modeled as a non-circular cylindrical shell with simply-supported ends in this paper. The shell model doesn’t have end plates of the carbody and other equipments attached to actual carbody are neglected. We have applied the transfer matrix method (TMM) to the analysis of three-dimensional elastic vibration problems on the carbody. We also made a 1/12 size carbody model for experimental studies to verify the validity of the numerical simulation. The model has end plates and was placed on soft sponge at both ends of the model to emulate the freely-support. The modal analysis was applied to the experimental model, and natural frequencies and mode shapes of vibration were measured. Comparing the results by TMM and the experiment, natural frequencies and mode shapes of vibration for lower modes show good agreement each other in spite of differences of boundary conditions.

Asymmetric Free Vibrations of Layered Conical Shells

1982 ◽  
Vol 104 (2) ◽  
pp. 453-462 ◽  
Author(s):  
K. Chandrasekaran ◽  
V. Ramamurti
Keyword(s):  
Natural Frequencies ◽  
Middle Surface ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Orthotropic Materials ◽  
Conical Shells ◽  
Shell Models ◽  
Theoretical Predictions ◽  
Parametric Studies ◽  
Ritz Procedure

Asymmetric free vibrations of layered truncated conical shells are studied. Individual layers made of special orthotropic materials and both symmetric and asymmetric stacking with respect to the middle surface are considered. An energy-method based on the Rayleigh-Ritz procedure is employed. The influence of layer arrangements and that of the coupling between bending and stretching on the natural frequencies and mode-shapes are analyzed. Experimental results from tests on two shell models are provided for comparison with theoretical predictions. Numerical results based on extensive parametric studies are presented.

scholarly journals Free Vibrations of Tapered Horseshoe Circular Arch with Constant Volume

2020 ◽  
Vol 10 (16) ◽  
pp. 5431
Author(s):  
Byoung Koo Lee ◽  
Gweon Sik Kim ◽  
Sang Jin Oh ◽  
Tae Eun Lee
Keyword(s):  
Natural Frequencies ◽  
Quadratic Function ◽  
Free Vibrations ◽  
Constant Volume ◽  
Mode Shapes ◽  
Cross Sectional ◽  
Circular Arch ◽  
Taper Function ◽  
Parametric Studies ◽  
Sectional Shape

This paper presents free vibrations of the tapered horseshoe circular arch with a constant volume. The volume of the arch is constant, and the cross-sectional shape of the arch is square and circular. The taper function of the arch is a quadratic function. Differential equations with the boundary conditions that govern the free vibration of such arches are derived and numerically solved to calculate natural frequencies and mode shapes. The natural frequencies of this study agree well with those of the finite element ADINA. Parametric studies of the geometrical and cross-sectional properties of the arch on frequencies and mode shapes are performed and discussed.

A Study on the Free Vibration of the Prestressed Joined Cylindricalspherical Shell Structures

2013 ◽  
Vol 390 ◽  
pp. 207-214 ◽  
Author(s):  
Mahdi Yusefzad ◽  
Firouz Bakhtiari Nejad
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Shell Structure ◽  
Shell Theory ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Shell Structures ◽  
Mode Shapes ◽  
Free Boundary Conditions ◽  
Modal Test

The free vibration characteristics of the prestressed joined spherical–cylindrical shell with free-free boundary conditions are investigated. The Flügge shell theory and Rayleigh-Ritz energy method are applied in order to analyze the free vibration characteristics of the joined shell. In the modal test, the LMS software is used to calculate mode shapes and natural frequencies of the joined shell structure. The natural frequencies and mode shapes are calculated numerically and they are compared with those of the FEM and modal test to confirm the reliability of the analytical solution. The effects of the shallowness and length of the cylindrical shell to the free vibrational behavior of joined shell structure and the effect of internal pressure on the modal charactristics are investigated.

scholarly journals Free vibrations of axially functionally graded horseshoe arch

2021 ◽  
Vol 9 (3) ◽  
pp. 251-262
Author(s):  
Gweon Sik Kim ◽  
Sang Jin Oh ◽  
Tae Eun Lee ◽  
Byoung Koo Lee
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Free Vibration ◽  
Natural Frequencies ◽  
Mass Density ◽  
Quadratic Function ◽  
Free Vibrations ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Parametric Studies

This paper deals with free vibrations of the axially functionally graded (AFG) horseshoe arch. The modulus of elasticity and the mass density of AFG material of arch are chosen as a univariate quadratic function. The differential equations with the boundary conditions that govern the free vibration of such arch are derived and numerically solved to calculate natural frequencies and mode shapes. Natural frequencies of this study agree well with those of the finite element ADINA. Parametric studies of the geometrical and mechanical properties of the arch on frequencies and mode shapes are performed and extensively discussed.

scholarly journals ANALYTICAL AND NUMERICAL STUDIES OF FREE VIBRATIONS OF CYLINDRICAL SHELL WITH ACOUSTIC MEDIUM

2021 ◽  
Vol 83 (1) ◽  
pp. 35-48
Author(s):  
I.A. Dyachenko ◽  
A.A. Mironov
Keyword(s):  
Finite Element ◽  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Mutual Influence ◽  
Circular Cylindrical Shell ◽  
Middle Layer ◽  
Free Vibrations ◽  
Acoustic Medium ◽  
Compressible Medium ◽  
Full Spectrum

The research materials are related to the problem of ensuring vibration resistance of pipelines exposed to dynamic loads, for which increased vibration is the main cause of damage. The solution to this problem involves studying the parameters of free vibrations of the structure. The paper solves the problem of determining the natural frequencies and forms of vibrations of a section of a circular cylindrical shell filled with an medium considered in the acoustic approximation. The results of studies of the parameters of free vibrations were obtained both by the analytical method of shell theory based on the Kirchhoff-Love hypotheses, and using the finite element complex of engineering analysis ANSYS. It is shown that the influence of the medium density on the parameters of free vibrations of the shell depends on the ratio of the shell thickness to its radius it turns out to be significant only for the shape of vibrations associated with bending deformation, and insignificant for forms associated with deformations of the middle layer. A comparative analysis of the results of calculations obtained for models of compressible and incompressible medium shows that when solving the problem of determining the parameters of free vibrations of the shell, the compressibility of the medium can be neglected. At the same time, to solve practical problems that require taking into account the full spectrum of natural frequencies of the shell–medium system, a compressible medium model should be used, in which the results on the effect of shell stiffness on the frequency spectrum of the medium volume are obtained. When solving practical problems of pipeline systems vibration, the use of the finite element method in a coupled formulation is an effective tool that allows us to consider all physical processes taking into account their mutual influence on each other.

OUT-OF-PLANE FREE VIBRATIONS OF CIRCULAR STRIPS WITH VARIABLE BREADTH

2007 ◽  
Vol 07 (03) ◽  
pp. 403-423 ◽  
Author(s):  
BYOUNG KOO LEE ◽  
TAE EUN LEE ◽  
ATHOL J. CARR ◽  
SANG JIN OH
Keyword(s):  
Differential Equations ◽  
Natural Frequencies ◽  
Slenderness Ratio ◽  
Free Vibrations ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Out Of Plane ◽  
Angle Section ◽  
Parametric Studies ◽  
Experimental Validations

This paper deals with the out-of-plane free vibrations of circular strips with linearly varying breadth. In deriving the differential equations for such strips, the effects of the rotatory and torsional inertias and shear deformation are considered. The differential equations are numerically solved to calculate the natural frequencies and mode shapes. In the numerical examples, three end constraints, i.e. clamped–clamped, clamped-hinged and hinged–hinged ends, are considered. The five lowest frequency parameters and mode shapes are presented. The effects of the rotatory and torsional inertias, and shear parameter on the natural frequencies are evaluated. Parametric studies are carried out for the influence of following parameters of the strip on the natural frequencies: subtended angle, section ratio, thickness ratio, and slenderness ratio. Also presented are the experimental validations of the seven lowest predicted natural frequencies. The natural frequencies obtained by this study agree well with those by the finite element method for both the flexural and torsional modes.

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