• Proceedings of the KSR Conference
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• 2005.11a
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• pp.382-388
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• 2005

SMSC(Seoul Metropolitan Subway Corporation) is substantially taking the core role of mass transit system in Seoul Metropolitan area. When it was built, the design had challenged to sharp curved tracks less than 250m radius considering the protection of buildings and cultural properties as well as the connection to ground roads. Such circumstances have required a certain extent of slack in track geometry and therefore led to the construction of ballasted track with wooden sleepers. However, the dynamic force from running on sharp curved track has caused the misalignment and abnormal failure of track geometry, and it has resulted in a frequent maintenance and repair works which require a lot of cost and manpower. In this paper, we present the construction case of maintenance-free track system by using of concrete sleeper and elastic rail fastening system to ensure the safety of both passengers and trains, and to contribute the effective maintenance for track facilities of SMSC.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.189-195
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• 2003

The steel wheels are widely used in the passenger cars because of their low cost of production although the aluminum wheels have many advantages in their performance and appearance. It is known that the steering wheel vibration with steel wheels is generated more often than one with aluminum wheels. Both the constant velocity driving test and the m up test are carried out in this study to analyze the causes and path of the steering wheel vibration generated from the steel wheels. And this study shows that the steering wheel vibration is affected by the fastening torque of the wheel mounting bolts between the steel wheel and the suspension disk.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.860-863
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• 2005

This work presents a study on development of a practical and quantitative technique for assessment of the structural health condition by PZT impedance-based technique associated with longitudinal wave propagation. The bolt fastening condition is adjusted by torque wrench In order to estimate the damage condition numerically, we suggest the evaluation method of impedance peak frequency shift $\Delta$F in this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.832-837
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• 2001

In this paper, we analyzed the characteristic of the broken section for bolts fastening the generator casing, and according to the frequency analysis, we grasped the characteristic of the excited force, traced the path of the exciting source so that we examined a factor of transient vibration of the generator casing. Even if it appears transient vibration again, we applied spring washer and more tensile bolt to the casing to minimize the fracture. By solving troubles of the generator rotor, we reduced the vibration amplitude to the normal condition. So we obtain much more the reliablility of the generator.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1243-1251
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• 2013

The purpose of this study is to investigate the influence of initial clamping force of tension clamp on the performance of an elastic rail fastening system used in sharp curve track. In this study, the initial clamping force and the increasing lateral wheel loads were conducted in the analytical and experimental study, i.e., finite element analysis, laboratory and field test. Using the analytical and experimental results, the performance of the tension clamp was investigated. It was found that the stress of tension clamp depends on the initial clamping force. Therefore the initial clamping force appeared to directly affect the compression stress of the tension clamp. It was found that the compression stress of tension clamp was transferred to the tensile stress by applied the lateral wheel load in service sharp curve track. Further, it was concluded that the initial clamping force was applied on the strengthening force for the tension clamp and then the appropriate initial clamping force was important to ensure a stable performance and long term endurance of tension clamp.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.241-249
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• 2017

A powerlock is used to transmit torque between two shafts, to protect important equipment from overloads, and to compensate for the misalignment of assembled shafts. In this study, the effect of the shapes of the inner rings, bolt-fastening force, and friction on power transmission performance of powerlocks is investigated. Finite element analysis and experiments were conducted for two cases, and the analysis results were validated. Analyses were carried out for inner rings of various shapes and for various values of bolt-fastening force and friction coefficient. The main factors that affect the torque transmission performance were investigated based on the analysis results.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11b
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• pp.3-38
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• 2000

Slope draperies in soil and rock are a well known method to avoid rockfalls into the roads or onto housings. Common wire mesh or a combination of wire mesh and wire rope nets are pinned to the slope by the means of fully grouted nails or anchors. Most of these installations have not been designed to stabilize the slope, but simply avoid the rocks from bouncing. The combination of soil- or rocknailing with a designable flexible facing system offers the advantage of a longterm stabilization of slopes and can replace other standard methods for slope stabilization. The capability to transfer axial and shear loads from the flexible facing system to the anchor points is most decisive for the design of the stabilization system. But the transfer of forces by mesh as pure surface protection devices is limited on account of their tensile strength and above all also by the possible force transmission to the anchoring points. Strong wire rope nets increase the performance for slope stabilizations with greater distances between nails and anchors and are widely used in Europe. However, they are comparatively expensive in relation to the protected surface. Today, special processes enable the production of diagonally structured mesh from high-tensile steel wire. These mesh provide tensile strengths comparable to wire rope nets. The interaction of mesh and fastening to nail / anchor has been investigated in comprehensive laboratory tests. This also in an effort to find a suitable fastening plates which allows an optimal utilization of the strength of the mesh in tangential (slope-parallel) as well as in vertical direction (perpendicular to the slope). The trials also confirmed that these new mesh, in combination with suitable plates, enable substantial pretensioning of the system. Such pretensioning increases the efficiency of the protection system. This restricts deformations in the surface section of critical slopes which might otherwise cause slides and movements as a result of dilatation. Suitable dimensioning models permit to correctly dimension such systems. The new mesh with the adapted fastening elements have already been installed in first pilot projects in Switzerland and Germany and provide useful information on handling and effects.

• Ocean and Polar Research
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• v.42 no.1
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• pp.77-88
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• 2020

This paper presents the coordinate systems used for trawl doors modeling, and provides matrix equations of connection between these systems. The projections of the forces acting on the door into axes of various coordinate systems were obtained, which were used in the door equilibrium equations. Six equilibrium conditions for the door as a solid were obtained: formulas that allow for the door area in plan to be determined; its weight in water; its mass; three moment equations for determining the position of the warp and backstrops fastening points to the door with triangular and quadrangular backstrop arrangements. It was found that the moment equilibrium equations of trawl doors are generally incompatible, which was not found by any of the authors who have previously conducted research into trawl doors. Using the Kronecker-Capelli theorem, the compatibility equation is obtained. This equation includes the coordinates of the backstrop fastening points to the door, which means that these points cannot be randomly selected. The technique of determining the warp and backstrops' fastening points position to the door is described. Conditions of directional (by angle of attack) and roll (in angle of roll) stability of the doors' equilibrium are presented. The equations presented in this paper comprise a mathematical model that allows, when designing the doors, to select optimal parameters, as well as to carry out adjustments for trawling purposes to ensure the stable movement of the doors and the entire trawl system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.257-262
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• 2017

As the size of electric products such as mobile phones and smart watches decrease, the bolts used to assemble these products should also be miniaturized. A miniature-sized bolt has to provide sufficient joining torque and anti-releasing torque to keep the components together. We studied a serrated bolt as a candidate for a miniature-sized fastener to increase the anti-releasing torque. In a serrated bolt, a serrated shape is formed on the bottom surface of the bolt head to create an obstacle to releasing. In this study, finite element analyses for the joining and releasing of bolts were carried out, and the anti-releasing performance was predicted. Based on the results of analyses using various numbers of serrations and fastening depths, the effects of the number of serrations and fastening depth on the anti-releasing performance were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7870-7877
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• 2015

In the case of CWR (Continuous welded rail) located on the railway bridge, the CWR has additional axial force due to interaction of bridge and track. Therefore, the CWR tracks located on the bridge have to secure the safety of running train and CWR track through mitigating influence for interaction of bridge and track. The railway design guide in Korea (KR C-08080) provides a certain value for property of longitudinal friction behavior of rail fastening system that is major parameter of interaction behavior by applying European codes. However, in order to apply to domestic railway, it is necessary to review property characteristics of the rail fastening system in actual use. In this paper, the experiment for longitudinal friction behavior of rail fastener applied to concrete track on the railway bridge in Korea was carried out, and statistical characteristic for property of the rail fastener was analyzed from the result of the experiment.