• Computers and Concrete
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• v.21 no.6
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• pp.661-667
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• 2018

The purpose of this study was to model and design a concrete catenary shell using a modern computer program without performing experiments. The modeling idea stems from the study by Pendergrast, but he listed supplementary items that should be improved in his paper. This study aims to resolve those issues and overcome the drawbacks of the study by Pendergrast. The process of experiment for the design of a catenary shell was reproduced by Grasshopper script. In order to ensure credibility, two models designed from the Grasshopper script were analyzed using a finite element program, SAP2000; one is a square-based catenary shell and the other is a special catenary shell called as the Naturtheater $Gr{\ddot{o}}tzingen$ shell, which was completed in 1977. First, the developed modeling approach was proved to be reasonable from the analysis of the square-based shell. The reliability was further confirmed by a comparison between the current and previous analysis results for the Naturtheater $Gr{\ddot{o}}tzingen$ shell.

• Korean Journal of Poultry Science
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• v.7 no.2
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• pp.47-53
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• 1980

This study was carried out to investigate the variations in the thickness of egg shell and egg shell membrane of Quail eggs from July 25, 1978 to September 7, 1978. No. of eggs used in this experiment was 520 okay and all the eggs were purchased from a farm located in Jinju city. The results obtained are summarized as follows: 1. Egg shells of quail were classified as white egg shell with large spots, egg shell with large spots, violet egg shell with small spots and beige egg shell with small spots by the exterior shell colour and their average egg weights were 8.993g, 8.866g, 8.403g and 8.109g, respectively. 2. Average egg shell thickness of white egg shell with large spots, egg. shell with large spots, violet egg shell with small spots and beige on shell with small spots were 0.171mm, 0.169mm, 0.160mm, and 0.156mm, respectively. 3. Average eggs shell membrane of white egg shell with large spots, egg shell with large spots, violet egg shell with small spots and beige egg shell with small spots were 0.0449mm, 0.0431mm, 0.0398mm, and 0.0397mm, respectively. 4. Negative correlation coefficient was found between egg shell thickness ana egg shell membrane thickness, but it was not significant. 5. Comparing quail egg with fowl egg, the thickness of quail egg shell was much thinner than that of fowl egg, but egg shell membrane thickness was similar between the two.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.68-77
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• 2003

Shell structure are widely used in a variety of engineering application and mathematical solution of shell structures are available only for a few special cases. The solution of shell structure is more complicated when it has such condition as winker foundation, variable thickness and other problem. In this paper, a simple finite element method is presented for the analysis of axisymmetric several types of shell structure subjected to axisymmetric loads and having uniform and varying wall thickness on elastic foundation. The method is based on the analogy with a beam on elastic foundation (BEF), foundation stiffness matrix where the foundation modulus and beam flexural rigidity are replaced by appropriate parameters pertaining to the shell under considerations. The technique is attractive for implementation on a numerical solution by means of a computer program coded in FORTRAN language with a few elements. To demonstrate this fact, it gives good results which compare well with SAP2000.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.160-165
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• 2008

Fluid loading of a vibrating cylindrical shell can change natural frequencies and vibration magnitudes of the shell and a vibrating cylindrical shell can also change acoustic pressure of fluid. The vibroacoustics of fluid-filled cylindrical shells need the coupled solution of Helmholtz equation and governing equation of a cylindrical shell with boundary conditions. This paper proposed the wall impedance of fluid-filled axisymmetric cylindrical shells, focusing on the inner fluid/shell interaction. To propose the impedance, shell displacements used the linear combination of in vacuo shell modes. Acoustic pressure prediction of fluid used Kirchchoff-Helmholtz Integral equation with Green function of the plane mode. For the demonstration of the proposed results, numerical applications on mufflers were conducted.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.1
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• pp.1-26
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• 2009

Cylindrical shells of isotropic and composite laminated materials are being used many engineering applications. This paper reviews the literature focusing on various aspects of shell research. The aspects of research receiving interest here are the cylindrical theory being used, the stress, buckling analysis and the impact analysis. The vibration analyses and stiffening characteristics of the cylindrical shell are investigated. The design optimizations of the cylindrical shell are reviewed. The studies on the conical and spherical shell are also reviewed. This review aticles contain 236 referencees.

• Korean Architects
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• v.4 no.14 s.14
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• pp.74-79
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• 1969

As we all know a large number of thin shell with the shape of E.P and H.P have been constructed. In this paper, we will be interested to the bending problem of thin translational shell. Two basic differential equations of shallow shell are to be used to derive approximate solution of it. Stress analysis of E.P. translational shell with constant thickness under uniform surface oad is to be given as an example. More exact solution formulated by K. Apeland can be found in the proceeding, Journal of the Engineering Mechanics Division, A.S.C.E., Feburary, 1961.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.868-870
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• 2003

In this paper, I have implemented the security system using shell script that periodically checking the security elements of unix system for security it transmit to a monitoring server and monitoring many clients. Agent of client executing by crontab scheduler, Environment of server to receive data use restricted TFTP in SunOS. And then, Because of using shell script, apply shell to system with flexible, control performance, and can meet on a sudden situation.

• Structural Engineering and Mechanics
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• v.39 no.4
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• pp.449-463
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• 2011

A free vibration analysis is made of a moderately-thick toroidal shell based on a shear deformation (Timoshenko-Mindlin) shell theory. This work represents an extension of earlier work by the authors which was based on a thin (Kirchoff-Love) shell theory. The analysis uses a modal approach in the circumferential direction, and numerical results are found using the differential quadrature method (DQM). The analysis is first developed for a shell of revolution of arbitrary meridian, and then specialized to a complete circular toroidal shell. A second analysis, based on the three-dimensional theory of elasticity, is presented to cover thick shells. The shear deformation theory is validated by comparing calculated results with previously published results for fifteen cases, found using thin shell theory, moderately-thick shell theory, and the theory of elasticity. Consistent agreement is observed in the comparison of different results. New frequency results are then given for moderately-thick and thick toroidal shells, considered to be completely free. The results indicate the usefulness of the shear deformation theory in determining natural frequencies for toroidal shells.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.62-67
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• 1995

A method for determining impulsive responses and acoustic radiation for submerged shells of finite length has been presented. The method is a modal-based method, and uses a surface variational principle to obtain data in the frequency domain. The fast Fourier transform technique is used to convert the data to the time domain. The surface pressure responses of a cylindrical shell with endcaps wer compared with those of an infinite shell. It was shown that the surface pressures coincide exactly before any significant reflections from the endcaps occur. Traces of different types of waves were identified from the dispersion relations of the infinite shell. The contributions of flexural and longitudinal waves and these due to the direct radiation from the driving force to the fluid pressure were demonstrated using near-field plots. The exchange of energy between the shell and fluid was examined for shells with and without bulkheads. It was shown that a significant amount of the energy which enters the fluid returns to the shell and most of the energy is dissipated in the shell. It was also shown that the shell with bulkheads radiate significantly more energy into the far-field than the empty shell.

• Journal of KSNVE
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• v.4 no.2
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• pp.163-175
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• 1994

An analytical method for nautral frequencies of a partially liquid- filled circular cylindrical shell with various boundary conditions is developed by means of the Stokes's transformation and Fourier series expansion on the basis of Sanders' shell equation. The liquid-shell coupled system is divided into two regions for convenient formulation. One is the empty shell region in which the Sanders' shell equations are formulated without the lipuid effect, the other is wetted shell region in which the shell equations are formulated with consideration of the liquid dynamic effect. The shell equations for each regions are combined by the geometry and the force continuities at the junction of the two regions. For the vibration relevant to the liquid motion, the velocity potential of liquid is assumed as a sum of linear combination of suitable harmonic functions in axial direction. The unknown parameters are selected to satisfy the boundary condition along the wetted shell surface. The natural frequencies of the liquid filled cylindraical shells with the clamped- free and the clamped-clamped boundary conditions examined in the previous works, are obtained by this analytical method. The results are compared with the previous works, and excllent agreement is found for the natural frequencies of the shells.