• Structural Engineering and Mechanics
• /
• v.59 no.6
• /
• pp.1121-1137
• /
• 2016

A large number of structure in the world were build with poor seismic details, with or without any lateral load resisting system like concentrically braced frames and steel plate shear walls. These structures can reveal deteriorating hysteretic behaviors with stiffness and strength degradation. Therefore, seismic retrofitting of such structures for drift control has vital importance. In this study a retrofit methodology has been developed, which involves diagonal bracing of steel frames with different cable arrangements. In the experimental and numerical program 5 different lateral load resisting system were tested and results compared with each other. The results indicated that multi-cable arrangements suggested in this study showed stable ductile behavior without any sudden decrease in strength. Due to the usage of more than one diagonal cable, fracture of any cable did not significantly affect the overall strength and deformation capacity of the system. In cable braced systems damages concentrated in the boundary zones of the cables and beams. That is why boundary zone must have enough stiffness and strength to resist tension field action of cables.

• Steel and Composite Structures
• /
• v.28 no.6
• /
• pp.681-690
• /
• 2018

This paper highlights results of some experimental work that deals with strengthening of bolted shear joints in thin-walled ferrocement structure where steel wires, bent into U-shape are considered as simple inserts around the bolt hole. The parameters investigated include the number of layers of wire mesh, edge distance of bolt hole, size and location of the inserts. Test results have shown that for small edge distance, failure occurred either in cleavage or shearing mode, and the strength of the joint increased with an increase in the edge distance. This continued up to an upper limit set by either tension or bearing failure. The experimental study further revealed that for a given edge distance the strength of a joint can significantly be enhanced by using U-inserts. The equations developed for predicting joint strength in ferrocement composites can also be modified to include the effects of the inserts with a good level of accuracy.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1129-1137
• /
• 2007

50kg NSI PCT(Prestress Concrete Timber, sleeper) is developed for the purpose of low maintenance cost, Extend life cycle, Track stability, Friendly Environment, Good running quality. In this study, as a part of research which is to make renovated NSI turnout, the main objective of this study is the optimization of PC sleeper's section, the number of PS tension wire. For this purpose, the finite element analysis was conducted to evaluate the serviceability and the safety of NSI PC sleeper developed.

• Clinics in Shoulder and Elbow
• /
• v.9 no.1
• /
• pp.124-129
• /
• 2006

Distal clavicular fracture frequently requires operative treatment due to high rate of non-union. The operative technique includes the tension band wiring, K- wire fixation, and cerclage wiring etc. Each method has disadvantages somewhat like pin migration or acromioclavicular joint injury and so on. For the distal clavicular fracture type 2a, because of its oblique fracture line, the cerclage wiring is suitable. We performed the cerclage wiring percutaneously under minimal incision without injury to periosteum for the patient who had the distal clavicular fracture type 2a, and the result was favorable.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.9
• /
• pp.825-831
• /
• 2006

As an increase of chip complexity and level of chip integration, chip input/output (I/O) pad pitches are also drastically reduced. With arrival of high complexity SoC (System on Chip) and SiP (System in Package) products, conventional horizontal type probe card showed its limitation on probing density for wafer level test. To enhance probing density, we proposed new vertical type probe card that has the $70{\mu}m$ probe needle with tungsten wire in $80{\mu}m$ micro-drilled hole in ceramic board. To minimize alignment error, micro-drilling conditions are optimized and epoxy-hardening conditions are also optimized to minimize planarity changes. To apply wafer level test for target devices (T5365 256M SDRAM), designed probe card was characterized by probe needle tension for test, contact resistance measurement, leakage current measurement and the planarity test. Compare to conventional probe card with minimum pitch of $50{\sim}125{\mu}m\;and\;2\;{\Omega}$ of average contact resistance, designed probe card showed only $22{\mu}$ of minimum pitch and $1.5{\Omega}$ of average contact resistance. And also, with the nature of vertical probing style, it showed comparably small contact scratch and it can be applied to bumping type chip test.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.3
• /
• pp.602-607
• /
• 2009

Most of explorer robot in past has the fixed magnitude and communicate with wire communication method. In case of various range of pipe's width and various angle in pipe inter structure, the exploring work is very difficult. Thus, in this paper, we design as dealing with spring tension with pushing out pipe exterior, and applied RF communication. We can accept good performance both structure change and improvement of ability, monitor and collect the defaults data in pipe inter structure. Newly designed and developed pipe explorer robot is very advantageous to carrying and driving as being small and law weight.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2265-2267
• /
• 2003

In this paper, the virtual reality system is tried to developed, which controls not only the sense of sight and hearing but also the sense of touch, In order to develope the sense of touch in this study, the stable tactual transaction system, based on summing up the basic algorithm and theory is embodied. Especially, the graphic deformation algorithm is developed in realtime with using the deformed FEM. To apply the FEM, a deformed material model is produced and then the graphic deformation with this model is able to force. Finally, the graphic transaction algorithm is deduced by the realtime calculation and simplification because the purpose of this system is to transact in real time. The result of this study is that the proposed system is possible to deform the graphics and transact the haptic in real time in PC. The simulation program has been made to prove this result.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.474-475
• /
• 2007

Wire electrical explosion(WEE) has been used for the production of fine metal particles. In WEE, electrical powder was stored and compressed into capacitor and released to produce fine particles through evaporation and condensation. In this study, the effect of applied voltage on the size of copper powders was investigated. High tension was added up to the explosion device by dividing 4 steps. At voltages lower than 5.2 kV, the fraction of powders finer than $44{\mu}m$ was almost negligible. The effectiveness of explosion increased sharply with increased voltage over 5.8 kV. At the highest voltage of 6.4 kV, more than 80% of explosion products were finer than $44{\mu}m$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.37 no.2
• /
• pp.63-70
• /
• 2019

Electric transmission towers are facilities to transport electrical power from a plant to an electrical substation. The towers are connected using wires considering the wire tension and the clearance from the ground or nearby objects. The wires are installed on a rights-of-way that is a strip of land used by electrical utilities to maintain the transmission line facilities. Trees and plants around transmission lines must be managed to keep the operation of these lines safe and reliable. This study proposed the use of a low-cost drone photogrammetry for the transmission line rights-of-way mapping. Aerial photogrammetry is carried out to generate a dense point cloud around the transmission lines from which a DSM (Digital Surface Model) and DTM (Digital Terrain Model) are created. The lines and nearby objects are separated using nDSM (normalized Digital Surface Model) and the noises are suppressed in the multiple image space for the geospatial analysis. The experimental result with drone images over two spans of transmission lines on a mountain area showed that the proposed method successfully generate the rights-of-way map with hazard nearby objects.

• Journal of the Society of Naval Architects of Korea
• /
• v.57 no.5
• /
• pp.254-261
• /
• 2020

The structural safety of hydraulic winch drum and the gears are estimated by the Finite Element Analysis (FEA) and the winch operation experiment. The mesh convergence test is performed and the applied force is the pressure on the drum converted from the rope tension in working condition. The stress of the drum calculated from the strain values of the winch operation experiment shows the agreement with that from the FEA. Most stress values are under the yield strength except for the small hole made for the wire rope fixation. The life of bearings in the drum is calculated using the life prediction formula with the reaction forces from the operation load. One of the two ball bearings shows the short life for impact condition, yet the real prototype winch system shows more life than the numerical value.