• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.359-364
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• 1998

The effects of boundary conditions on natural frequencies for the ring stiffened composite cylindrical shells are investigated by theoretical method. The Love's thin shell theory and the discrete stiffener theory with beam functions in the Ritz procedure are used to derive the frequency equation. Five different boundary conditions such as clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study. Also, the experimental investigation is presented to validate the theoretical results.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.534-541
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• 2015

This study was presented how to interpret a laminated cylindrical shell having both ends supported condition are simple, and by identifying the three-dimensional stress characteristics. The governing equations were using the concept of finite element assuming the conversion into ordinary differential equations and partial differential equations by numerical analysis using the finite strip method. In particular, a function performed for the three-dimensional laminated cylindrical shell having a simple support condition were analyzed for the case composed of a specific function of the beam consisting of a trigonometric function. Layer material and layer thickness of a steel or concrete, the cylindrical length and the like by varying the parameters variously examine the effects of multi-layer cylindrical shell.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.91-97
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• 2022

The Directed Energy Deposition (DED) is a representative metal additive manufacturing method. Owing to its strong point of repairment, its application is gradually spreading in aerospace applications, power generation, military components, and mold making. 5-axis cladding is needed to repair damage, such as wear and scratches on cylindrical surfaces to circular-shaped parts, including sleeves and liners. Furthermore, the condition of cladding on inclined parts must also be considered to prevent interference between the nozzle and the part. In this study, the effects of changes in scanning speed due to the 5-axis control system and differences from the height of laser beam irradiation due to inclination are evaluated among the items that should be additionally considered in 5-axis cladding compared to 3-axis cladding. Moreover, the trends of the width and height of the clad are identified by different tilting angles via single line cladding. Lastly, cladding methods on cylindrical surfaces at various angles are proposed to enhance the clad quality and post-processing efficacy. These results can be applied with 5-axis cladding on inclined surfaces, including cylindrical surfaces.

• Advances in concrete construction
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• v.16 no.4
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• pp.189-203
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• 2023

This study investigates the bending and stability properties of cylindrical constructions, with a focus on their use in the design and implementation of sporting equipment. The work focuses on a cylindrical construction resembling nanomotors, similar to components seen in sports equipment, using mathematical modeling based on high-order beam theory and nonlocal strain gradient theory. The analysis provides important insights into the dynamic behavior of these systems, revealing light on the impact of numerous factors such as rotational velocity, section change rate, and structural dimensions. The results show a relationship between angular velocity growth and section change rate, which leads to an increase in fundamental frequency values. Furthermore, the research emphasizes the effect of structural factors on dynamic deflection, giving critical information for increasing the stability and performance of sporting equipment. This study adds to the area of sports engineering by providing a more nuanced understanding of how cylindrical constructions react under diverse settings. The results will help to guide the design and manufacturing processes of sports equipment, assuring improved stability and performance for players across a wide range of sports.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.644-647
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• 1996

In this study the theoretical minimum resolution analysis of an active vision system using laser range finder is performed for surrounding recognition and 3D data acquisition in unknown environment. The laser range finder consists of a slitted laser beam generator, a scanning mechanism, CCD camera, and a signal processing unit. A laser beam from laser source is slitted by a set of cylindrical lenses and the slitted laser beam is emitted up and down and rotates by the scanning mechanism. The image of laser beam reflected on the surface of an object is engraved on the CCD array. In the result, the resolution of range data in laser range finder is depend on distance between lens center of CCD camera and light emitter, view and beam angles, and parameters of CCD camera.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.118-122
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• 1997

This paper presents a 3d image processing which uses neural networks to combine a 2D vision camera and a laser slit beam. A laser slit beam from laser source is slitted by a set of cylindrical lenses and the line image of the slit beam on the object is used to estimate the object parameters. The neural networks allow to get the 3D image parameters such as the size, the position and the orientation form the line image without knowing the camera intrinsic parameters.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1045-1050
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• 2007

Equations of motion of rotating cantilever curved beams are derived based on a dynamic modeling method developed in this paper. The Kane's method is employed to derive the equations of motion. Different from the classical linear modeling method which employs two cylindrical deformation variables, the present modeling method employs a non-cylindrical variable along with a cylindrical variable to describe the elastic deformation. The derived equations (governing the stretching and the bending motions) are coupled but linear. So they can be directly used for the vibration analysis. The coupling effect between the stretching and the bending motions which could not be considered in the conventional modeling method is considered in this modeling method. The natural frequencies of the rotating curved beams versus the rotating speed are calculated for various radii of curvature and hub radius ratios.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.290-297
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• 2002

Vibration experiments have been performed to observe the analytic characteristics of power How finite element method(PFFEM) for the reinforced cylindrical structure. For this, the vibration experimental results are compared with the numerical solutions obtained by PFFEM in medium-to-high frequency ranges. Input Power into the experimental structure is measured using the impedance head adhered to the exciter, and that input power is used for the vibration analysis. Using the developed PFFEM program(PFADS), the reinforced cylindrical structure modeled by beam and plate elements is analyzed, and very reliable results for PFFEM are obtained by the comparisons of the experimental results.

• Journal of KSNVE
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• v.7 no.2
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• pp.331-345
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• 1997

A theoretical formulation for the analysis of free vibration of clamped-free cylindrical shells with plates attached at arbitrary axial position(s) was completed and it was programed to get the numerical results which yield natural frequencies and mode shape of the combined system of the plate and the shells. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis. The results shows good agreement with those of ANSYS and test results in frequencies and mode shapes. The method developed herein is likely to be used for the analysis of the free vibration of the clamped-free circular cylindrical shells with any kinds of lids such as hollow circular plates, conical shells, spherical shells, or semi-spherical shells.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.355.2-355
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• 2002

The receptance method was applied for the analysis of a cylindrical shell with a spherical cap attached at an arbitrary axial position of the shell. The boundary condition of the shell considered here was clamped-free condition. Before the analysis of the shell/spherical cap combined structure, natural frequencies of the cap and the shell were calculated separately and then they were used in the calculation of the frequencies of the combined structure by the receptance method. (omitted)