• Computers and Concrete
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• v.28 no.6
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• pp.559-566
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• 2021

In this paper, frequency analysis has been done for functionally graded cylindrical shell with ring supports using Sander's shell theory. The vibrations of rotating cylindrical shells are analyzed for different physical factors. The fundamental natural frequency is investigated for different parameters such as: ratios of length-to-diameter ring supports. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. The frequencies for different position of ring supports are obtained in the form of bell shaped. The backward frequencies increases and forward frequencies decrease on increasing the rotating speed. The results generated furnish the evidence regarding applicability of present shell model and also verified by earlier published literature.

• Advances in concrete construction
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• v.14 no.1
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• pp.35-43
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• 2022

Based on novel Galerkin's technique, the theoretical study gives a prediction to estimate the vibrations of FG rotating cylindrical shell. Terms of ring supports have been introduced by a polynomial function. Three different laws of volume fraction are utilized for the vibration of cylindrical shells. Variation frequencies with the locations of ring supports have been analyzed and these ring supports are placed round the circumferential direction. The base of this approach is an approximate estimation of eigenvalues of proper functions which are the results of solutions of vibrating equation. Each longitudinal wave number corresponds to a particular boundary condition. The results are given in tabular and graphical forms. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing length-to-radius ratio. There is a new form of frequencies is obtained for different positions of ring supports, which is bell shaped. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases.

• Advances in concrete construction
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• v.9 no.6
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• pp.557-568
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• 2020

In this study, the impact of ring supports around the shell circumferential has been examined for their various positions along the shell axial length using Rayleigh-Ritz formulation. These shells are stiffened by rings in the tangential direction. For isotropic materials, the physical properties are same everywhere where the laminated and functionally graded materials, they vary from point to point. Here the shell material has been taken as functionally graded material. The influence of the ring supports is investigated at various positions. These variations have been plotted against the locations of ring supports for three values of length-to-diameter ratios. Effect of ring supports with middle layer thickness is presented using the Rayleigh-Ritz procedure with three different conditions. The influence of the positions of ring supports for clamped-clamped is more visible than simply supported and clamped-free end conditions. The frequency first increases and gain maximum value in the midway of the shell length and then lowers down. The Lagrangian functional is created by adding the energy expressions for the shell and rings. The axial modal deformations are approximated by making use of the beam functions. The comparisons of frequencies have been made for efficiency and robustness for the present numerical procedure. Throughout the computation, it is observed that the frequency behavior for the boundary conditions follow as; clamped-clamped, simply supported-simply supported frequency curves are higher than that of clamped-simply curves. To generate the fundamental natural frequencies and for better accuracy and effectiveness, the computer software MATLAB is used.

• Structural Engineering and Mechanics
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• v.2 no.4
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• pp.369-381
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• 1994

This paper is concerned with the elastic buckling of cylindrical shells with internal rigid ring supports. The internal supports impose a zero lateral deflection constraint on the buckling modes at their locations. An automated Rayleigh-Ritz method is presented for solving this buckling problem. The method can handle any combination of end conditions and any number of internal supports. Moreover, it is simple to code and can yield very accurate solutions. New buckling results for cylindrical shells with a single internal ring support, and under lateral pressure and hydrostatic pressure, are given in the form of design charts. These results should be valuable to engineering designers.

• Earthquakes and Structures
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• v.24 no.4
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• pp.237-245
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• 2023

Based on novel Galerkin's technique, the theoretical study gives a prediction to estimate the vibrations of FG rotating cylindrical shell. Terms of ring supports have been introduced by a polynomial function. Three different laws of volume fraction are utilized for the vibration of cylindrical shells. Variation frequencies with the locations of ring supports have been analyzed and these ring supports are placed round the circumferential direction. The base of this approach is an approximate estimation of eigenvalues of proper functions which are the results of solutions of vibrating equation. Each longitudinal wave number corresponds to a particular boundary condition. The results are given in tabular and graphical forms. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing length-to-radius ratio. There is a new form of frequencies is obtained for different positions of ring supports, which is bell shaped. Moreover, on increasing the rotating speed, the backward frequencies increase and forward frequencies decreases.

• Structural Engineering and Mechanics
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• v.88 no.2
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• pp.109-115
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• 2023

In this paper, frequencies of zigzag structure of carbon nanotubes isinvestigated based on Donnell shell theory. These tubes are wrapped with the ring supports in the axial direction. The fundamental frequency curves displayed in article show the dependence of vibrations attributes to zigzag single walled carbon nanotubes. Various zigzag indices are introduced against the variation of length to predict the vibration. Also, the influence of ring supports is sketched with proposed structure for frequency analysis. The frequencies of zigzag tube decreases as the length increases. It is observed that the frequencies decreases with ring support and have higher frequencies without ring. The problem is formulated using Partial Differential Equation. Three expressions of modal deformation displacement functions is used for the elimination of temporal variation to form the solution in the eigen from. For the stability of present study the results are compared with experimentally and numerically in the open text.

• Computers and Concrete
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• v.25 no.5
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• pp.411-425
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• 2020

In this paper, the shell material has been taken as functionally graded material and their material quantity is located by the exponential volume fraction law. Moreover, the impact of ring supports around the shell circumference has been examined for their various positions along the shell axial length. These rings support restraints the radial displacement in the transverse direction. While the axial modal deformation functions have been estimated by characteristic beam functions and nature of materials used for construction of cylindrical shells. The fundamental natural frequency of cylindrical shell of parameter versus ratios of length- and height-to-radius for a wide range has been reported and investigated through the study. In addition, by increasing height-to-radius ratio resulting frequencies also increase and frequencies decrease on ratio of length-to-radius. Though the trends of frequency values of both ratios are converse to each other with three different boundary conditions. Also it is examined the position of ring supports with length-to radius ratio, height-to-radius ratio and varying the exponent of volume fraction. MATLAB software package has been utilized for extracting shell frequency spectra. The obtained results are confirmed by comparing with available literature.

• Steel and Composite Structures
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• v.37 no.2
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• pp.137-150
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• 2020

In this research work, the analytical rotating vibration for functionally graded shell with ring supports are restricted to some volume fraction laws based on Rayleigh-Ritz technique. The frequencies of functionally grade cylindrical shells have been investigated for the distribution of material composition of material with two kinds of material. Stability of a cylindrical shell depends highly on these aspects of material with ring supports. The frequency behavior is investigated with fraction laws versus circumferential wave number, length-to-radius and height-to-radius ratios. The frequencies are higher for higher values of circumferential wave number. The frequency first increases and gain maximum value with the increase of circumferential wave mode. Moreover, the effect of angular speed is also investigated. It is examined that the backward and forward frequencies increases and decreases on increasing the ratio of height- and length-to-radius ratios.

• Advances in concrete construction
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• v.14 no.5
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• pp.309-315
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• 2022

This paper depicts the diagram of cylindrical shells as an essential idea. It centers around an outline of exploration and use of cylindrical shell in expansive current circumstance. In view of investigation of the current and prospect of model as a piece of present exploration work, a straightforward contextual analysis is examined with Love's shell theory based on Galerkin's method. The cylindrical shells are attached from one end of the cylindrical shells. The frequencies of ring support shells are investigated against the half axial wave mode. The frequencies increase on increasing the half axial wave mode. Also, the frequencies are downsized with ring supports. The software MATLAB is preferred to others because in this software computing coding is very easy to do. Just single command 'eig' furnishes shell frequencies and mode shapes by calculating eigenvalues and eigenvectors respectively. The shell vibration frequencies for cylindrical shells are compared with those results found in the open literature.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.644-649
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• 2014

Analytical model is derived for the far-field acoustic radiation from machinery installed inside cylindrical shell. The analytical model includes the effect of fluid loading and interactions between periodic ring supports. Transmitted force from machine to a shell can be different by the impedance of shell. In this paper the transmitted force from machinery to a infinite shell through vibration isolator is considered by the impedance of shell. The effect of the shell impedance for acoustic radiation is investigated.