• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1242-1247
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• 2007

An active application of concrete track is being expected for the future constructions of Korea railroad. For the successful construction and design in embankment section, the roadbed behavior should be reasonably estimated using the proper analysis method. In this research, behaviors of reinforced roadbed constructed with the determined stiffness and thickness at embankment section were estimated through various design parameters and numerical analysis. A three dimensional finite element method was employed to determine the proper reinforced roadbed thickness at embankment section. The displacement and vertical stress caused by train loading were estimated and compared with the field test results. The bearing characteristics of concrete track roadbed were presented. Moreover, the method to determine thickness of reinforced roadbed was proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.329-334
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• 2001

Recently, the high precision technology can not be developed continuously if we don't have anti vibration technology. Vibration isolation technology using an air spring and laminated robber bearing is widely used because it has excellent vibration isolation characteristics. We developed high precision vibration table with two good element(air spring and LRB) for semiconductor factory. Air Spring is used for isolating the vertical vibration and LRB is used for isolating the horizontal Vibration. As a result, It has D-Class degree in BBR-Criteria. In this paper, we talk about orifice characteristics in the self-damped air spring and design flow of the laminated robber bearing. The orifice characteristics is delicate shade of length and diameter. When we do experimentation to find orifice characteristics, length is fixed and diameter is changed. The orifice diameter is the wider and the air spring stiffness is the softer.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.594-596
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• 2007

Using an oedometer cell instrumented to measure the evolution of electromagnetic properties, small strain stiffness, and temperature, we conducted consolidation tests on four types of sediments. The tested specimens include sediments with different gas hydrate saturation at four stages of loading. The test results show that the electromagnetic and mechanical properties of hydrate-bearing marine sediments are governed by the vertical effective stress, stress history, porosity, hydrate saturation, fabric, ionic concentration of the pore fluid, and temperature. The results also show that permittivity and electrical conductivity data can be combined to estimate hydrate volume fraction in laboratory sediments, methodology that might eventually be extended for estimation of hydrate concentrations in field settings.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.123-128
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• 1997

In-situ bearing metal temperature and shaft vibration are measured for an unload type and a preload type, m=0.87, of vertical guide bearing for hydraulic pump-turbines. Guide bearing is a tiltingpad type journal bearing consisting of eight pads whose diameter is 1,450 mm. Rotational speed is 450 rpm. Both the bearing metal temperature and the shaft vibration are very high in the unload type but are slight in the preload type, comparatively. The bearing metal temperature is decreased due to the increase of cooling effect by the increase of preload and the shaft vibration is decreased due to the increase of bearing stiffness. It is concluded that the preload effect of a guide bearing for hydraulic pump-turbines has a large influence on the bearing metal temperature and the shaft vibration.

• 산업기술연구
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• 제19권
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• pp.351-359
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• 1999

If the tactile sense is introduced to engineering and industries, it may provide more realistic virtual tactile sensing to human and it is possible to develop product that satisfy various consumer's taste. This paper presents a compliance emulator system as a new concept of tactile reproduction simulator which uses magnetic levitation in order to minimize friction and emulates compliance only along the vertical direction. Compliance is one of the important mechanical properties of the object related to tactile sensing of the human. The implemented system equipped with an analog LVDT sensor for a position sensor and employs a PD control with gravity compensation to emulate the specified compliance. To compensate the limited range of the system, the method of attaching the spring with various magnitude of stiffness to the system is adopted and its preliminary test is performed to confirm the validity of the method.

• 한국공작기계학회논문집
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• 제13권1호
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• pp.88-93
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• 2004

In general, a fundamental structural design consideration for an automobile is the overall dynamic behavior in bending and torsion. Dynamic behavior of the automobile are mainly influenced by the structural stiffness of B.I.W.(body-in-white) and the physical property of trim components. In this paper, the modeling techniques for various trim components of middle-sized bus are presented, and the dynamic effects of the trim components on the vibration characteristics of the bus are investigated. The $1^{st}$ torsional frequency is decreased by attaching windshield and backlite to the B.I.W., but the $1^{st}$ vertical bending frequency and the $1^{st}$ lateral bending frequency are increased. The natural frequencies of the bus are decreased by attaching doors and windows. And also, the natural frequencies of the bus are large decreased by attaching seats, instrument panel etc. The study shows that the dynamic characteristics of the bus can be effectively predicted in the initial design stage.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.175-175
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• 2012

Proper shaft alignment is one of the most important actions during the design of the propulsion system. The stiffness of recently designed marine propulsion shafting has been increasing remarkably, whereas hull structures have become more likely to deform as a result of optimized design of the scantlings and the high tensile steel. Therefore, to obtain the optimum status in shafting alignment at the design stage, it is strongly recommended that the change of bearing reaction force depending on ballast/load condition, the bending moment force occurred by propeller thrust, elastic deformation of bearing occurred by vertical load of shaft mass and etc., should be considered. This paper dealing with introduction of shaft alignment concerning long shaft for high speed vessel and review its reliability evaluation theoretically.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.115-124
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• 2003

A prestressed concrete slab bridge is analyzed by the specially orthotropic laminates theory. Both the geometry and the material of the cross section of the slab are considered symmetrical with respect to the mid-surface so that the bending extension coupling stiffness, $B_{ij}=0$, and $D_{16}=D_{26}=0$. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of rule of mixture. This bridge with simple support is under uniformly distributed vertical and axial loads. In this paper, the finite difference method and the beam theory are used for analysis. The result of beam analysis is modified to obtain the solution of the plate analysis.

• 한국소음진동공학회논문집
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• 제13권1호
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• pp.63-69
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• 2003

The ordinary differential equations governing free vibrations of elastic horizontally curved beams are derived, in which the effects of rotatory inertia and shear deformation as well as the effects of both vertical and torsional inertias are included. Frequencies and mode shapes are computed numerically for parabolic curved beams with the hinged-hinged, hinged-clamped and clamped-clamped ends. Comparisons of natural frequencies between this study and ADINA are made to validate the theories and numerical methods developed herein. The lowest three natural frequency parameters are reported. with and without the effects of rotatory inertia and shear deformation. as functions of the three non-dimensional system parameters: the horizontal rise to span length ratio. the slenderness ratio and the stiffness parameter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.958-968
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• 1994

This paper presents a dynamic analysis of the high-speed spindle system for vertical machining center using finite techniques. The computed natural frequencies are compared with the measured frequencies obtained from experimental modal analysis. The results show that the bending and twisting deformations of the spindle housing dominate in the lowest modes owing to low dynamic stiffness of the housing structure. The design parameters in the analysis are : (a) panel thickness of the housing (b ) height of the housing, and (c) spindle-to-column distance of the housing. Through sensitivity analysis and optimizing simulation considering design constraints, an optimal design of the spindle system has been obtained.