• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.721-724
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• 2006

In the development of sheet-handling machinery, it is important to predict the static and dynamic behavior of the sheets with a high degree of reliability. Flexible media is very thin, very light and very flexible so it behaves geometric nonlinearity of large displacement and large rotation but small strain. In this paper, static and dynamic analyses of flexible media are performed by dynamic FEM considering geometric nonlinearity. Mass and tangent stiffness matrices based on the Co-rotational(CR) approach are derived and numerical simulations are performed by full Newton-Raphson(FNR) method and Newmark integration scheme.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.1004-1009
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• 2002

There are four servo systems in a DVD drive such as a focus servo system, a tracking servo system, a sled servo system and a spindle servo system. Focus servo system maintains relative distance between lens and disk. In this paper, two plant models for the focus servo system will be presented. One of them is conventional and the other is newly developed. Focus error signal between lens and disk is detected using LDV 2 beam method. The system is observable and all states are estimated. Full states feedback controller and minimum order observed are designed using those states. Impulse responses are simulated. And experiment is performed to compare with responses of conventional model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.1015-1021
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• 2002

Optical disk is the media which is used generally in data storage device, but it has a disadvantage in the vibration by spinning and the shock. For overcoming these disadvantage, we must control the optical disk to minimize the focusing error and tacking error. The present study investigates the disk profile for minimizing the focusing error subjected to environmental shock and weight of the disk. In this study, the disk is assumed to be a cantilever beam to determine the disk profile for the minimum displacement as to the shock considering only the first mode. Also, for the optimally determined profile by ADS program this paper recalculate the robust caltilever profile by using orthogonal array and ANOM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.906-911
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• 2004

In the development of sheet-handling machinery, it is important to be able to predict the italic and dynamic behavior of the sheets with a high degree of reliability because the sheets are fed and stacked at such a high speed. In this paper, a spring-mass-beam model is introduced. This model consists of rotational springs, shear springs and masses. The formulations for static and dynamic behavior of sheets are introduced. And some simulations are presented for static and dynamic cases.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.461-468
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• 2001

지진등에 의해 유발된 동 하중에 의한 지반-구조물 계의 응답은 지반-구조물사이의 경계에서의 마찰특성과 미끄러짐에 의해 크게 영향을 받게 된다 본 논문에서는 진동대(Shaking table)를 이용하여 조립토와 건설재료(Steel)의 경계에서 지반으로부터 지중구조물에 전달되는 전단응력 의 전달정도를 파악하기 위한 실험을 실시하였다. 본 실험에서 설정한 미끌어짐속도 범위내에서는 미끄러짐속도 변화에 따른 조립토와 건설재료(Steel)사이의 동마찰계수의 변화가 작다는 사실이 관찰되었다. 그리고 조립토의 평균유효입경의 변화가 동마찰계수에 미치는 영향도 함께 조사되었다. 또한 이 동마찰계수를 같은 조립토에 대한 평면변형률시험을 통해 얻어진 최대내부마찰각으로부터 구한 마찰계수와 비교하여 정량화하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.388-391
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• 2006

In the development of sheet-handling machinery, it is important to predict the static and dynamic behavior of the sheets with a high degree of reliability because the sheets are fed and stacked at such a high speed. Flexible media behaves geometric nonlinearity of large displacement and small strain. In this paper, static and dynamic analyses of flexible media are performed by FEM considering geometric nonlinearity. Linear stiffness matrix and geometric nonlinear stiffness matrix based on the Co-rotational(CR) approach are derived and numerical simulations are performed by Updated Newton-Raphson(UNR) method and Newmark integration scheme.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.569-572
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• 2005

In many machines handling lightweight and flexible media, such as automated teller machines(ATM) and printers etc., the media must transit an open space. In the paper feeding mechanism, it is important to feed the sheet without jamming under any conditions. To avoid sheet jamming, first we need to predict the behavior of the sheet exactly. The nonlinear theory of the dynamic elastica has often been used to a nonlinear dynamic deflection model. In this paper, the governing equation is derived and simulated by the finite difference method. The analysis has to include aerodynamic effect for more exact behavior analysis. For verification of the numerical simulation, the experiments were performed using high-speed camera and feeding mechanism. The experimental results show good agreement with the numerical simulations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.596-599
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• 2004

The media transport systems, such as printers, copiers, facsimile, ATMs, cameras, etc., have been widely used and being developed rapidly. In the development of those systems, the media feeding mechanism is an important key technology for the design and development of the media transport systems. In this paper, a multi-degree of freedom sheet model with dynamic contact conditions is presented to understand the mechanism of sticking and jamming. A sheet is modelled as a cantilever beam and the feeding velocity is assumed to be constant. The relation between the feeding velocity and the coefficient of friction for guaranteeing stable feeding is presented. Simulations are performed for a horizontal linear guide and a oblique linear guide, calculating the contact force and contact states of mass points.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.600-605
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• 2004

In many machines handling lightweight and flexible media such as magnetic tape drives, xerographic copiers and sewing machines, the media must transit an open space. It is important to predict the static and dynamic behavior of the sheets with a high degree of reliability. The nonlinear theory of the dynamic elastica has often been used to a nonlinear dynamic deflection model. In this paper, the governing equation is derived and simulated by the finite differential method. The parametric cubic curve is applied for defining the guide shape. The dynamic contact conditions suggested by Klarbring is used to predict the direction of the flexible media according to the initial velocity and the friction coefficient. The analysis is also compared to the conventional model, showing that after contacting a $45^{\circ}$ wall, the directions of flexible media of two models are different.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.58-66
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• 2011

This study presents the behavior characteristics of buried three-layered pipeline subjected to pile driving loads. The analysis considered the driving energy caused by 7 tonf of ram weight and 1.2m of stroke. Also the distance from vibration resource to pipeline varies in 5m to 30m. The vibration velocity and stress are investigated at the center of pipeline in longitudinal direction. In the same cover depth, attenuation ratio of vibration velocity and von Mises stresses for distance increment has shown a decreasing trend. The maximum stress occurs at the top and bottom for the inner pipe, however, an irregular stress distribution is found for the outer pipe.