• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1008-1011
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• 2001

The purpose of this paper is to evaluate the chip breakability during turning using the experimental equation, which is developed by an orthogonal array method. The chip breaking index(CB), non-dimensional parameter is used in the evaluation of chip breakability. The analysis of variance(ANOVA)-test has been used to check the significance of cutting parameters. And using the result of ANOVA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed.

• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.3-10
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• 1994

This study examines fracture characteristics of wire rope of 6$\times$37+FC 14mm B degree, Which has been widely used for the strength support for machinery, cranes and shipping. The examination Is based on the fellowing experimental conditions. Firstly, this study analyzes the effect of the strength of wlre rope. When number of broken wires is occuring at the level of 5%, 10% and 15% degree respectively in the following two cases：1) Case of broken down to each strand equally. 2) Case of broken down to one strand only. Secondly, this study analyzes the effect of corrosion on the strength of wire rope. Corrosion times are 72hours, 144hours and 216hours corrosion respectively under following conditions. 1) Case of only a corrosion without wire breaking. 2) Case of corrosion after 5% degree wire breaking to each strand equally. Some outcomes of these experiment are as follows. 1) From the of tension test, We can find that the ratio of strength reduction case of wire broke down to one strand concentrically is greater than that ratio case of broke down to each strand equally. 2) From the corrosion test, We can also find that the ratio of strength reduction case of corroded after 5% degree wire breaking to each strand equally Is greater than that ratio case of corroded without wire breaking. 3) After comparing theoretical fracture load of wires with experimental fracture load of wires, we can find the fracture load of the case of broken down to each strand equally is most similar to theoretical fracture load. 4) It is proposed that safety rules on wire rope in the Industrial safety and healthy labor of law have to change “breaking over 10% of number of wires in one strand of wire rope(excluded filler wire )”has to be replaced by“breaking over 10% of number of all wires in all strand of wire rope(excluded filler wire)”

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.899-904
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• 2012

In recent years, a lot of research was done for earth fault protection in ungrounded dc power supply system. As a result, selective-breaking integrated protective relaying system is developed in progress and is currently field-testing are planned. Algorithm on a PC using PSCAD done a lot of testing before performing field tests, but in this study developed algorithms and functions needed to determine whether they were operating normally. Therefore, simulated system is similar to the actual situation was required and made. selective-breaking algorithm verification and validation was performed with simulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.502-505
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• 2003

The accidnet of breaking insulator rod leads to inturruption of moving the subway. We investigate the analysis of analysis of breaking accident of FRP insulator rod installed in dead section for catenary feeding system. To analysis of accident reason, SEM is used to analysis microscopic struture on surface of cross section of broken FRP insulator rod. At the same time, we examine the chage of atomic amount on solace of accident insulator through EDX analysis. Also, the test for tensional breaking load is condoled to check the mechanical strength.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.8
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• pp.396-402
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• 2006

Even the case DC circuit Breaker have good quality for interruption of high current like heavy load current, short-circuit current, the verification for small current breaking capability of circuit breaker should be performed. It comes from the reason DC small current breaking failure can be lead to break out second heavy fault condition and in the long run substation shutdown. In this paper, we can find the characteristics of DC small current and international test standard discription about small current breaking and one of the proper solution to get over it.

• Journal of Ocean Engineering and Technology
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• v.14 no.1
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• pp.6-10
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• 2000

In this paper various methods of determining of wave loads acting ofshore structures including impact load due to breaking wave are studied and corresponding model test was performed. In the theoretical approach wave load by nonbreaking wave and impact load by breaking wave is determined by Morrison's equation Goda's equation and impact wave equation, In the experimental approach wave load by nonbreaking wave acting on cylindrical pile used in offshore structures is determined by measuring the strain on a cylindrical pile and compared with theoretical calue. in the numerical approach impact load by breaking wave acting on a modeled cylindrical pile is calculated by usign ANSYS FEM program and compared with theoretical value. It is found that the experimental and numerical results are comparable to theoretical results, Thus the determination of wave load acting on offshore structures can be obtained by a proposed methods and it acceptable.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.28-33
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• 2015

The icebreaking research vessel ARAON had her second ice trial in the Arctic Ocean from July 16 to August 12, 2010. In this study, the ice loads measured during the “general” operation and “ice breaking” operation in ice-covered waters were analyzed and compared. Whereas the “general” operation stands for the voyage in the water partially covered by ice, the “ice breaking” operation involved substantial ice floes for the ice breaking performance test. Based on the measured data, comparisons of the relationship between the ship speed and ice load, and between the locations of strain gauges and ice loads were investigated. Peak stresses higher than 20 MPa were found. The longitudinal and vertical correlations between the measurement location and ice load were analyzed, and the probability of peak stress was calculated. As a result, the probability function for higher ice loads during both operation modes was expressed in an exponential and power forms.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.3
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• pp.246-254
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• 2007

The scanning laser source (SLS) technique is a promising new laser ultrasonic tool for the detection of small surface-breaking defects. The SLS approach is based on monitoring the changes in laser-generated ultrasound as a laser source is scanned over a defect. Changes in amplitude and frequency content are observed for ultrasound generated by the laser over uniform and defective areas. The SLS technique uses a point or a short line-focused high-power laser beam which is swept across the test specimen surface and passes over surface-breaking or subsurface flaws. The ultrasonic signal that arrives at the Rayleigh wave speed is monitored as the SLS is scanned. It is found that the amplitude and frequency of the measured ultrasonic signal have specific variations when the laser source approaches, passes over and moves behind the defect. In this paper, the setup for SLS experiments with full B-scan capability is described and SLS signatures from small surface-breaking and subsurface flaws are discussed using a point or short line focused laser source.

• Explosives and Blasting
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• v.24 no.1
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• pp.49-56
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• 2006

There are many restrictions with a rock breaking method by using explosives in the urban area due to such safety problems as vibration, noise, and flying rock. Therefore, the use of FINECKER Plus which is mainly used as a rock breaking method (Ministry of Construction and Transportation, 2003) is gradually increasing. Accordingly, construction cases applying FINECKER Plus to the construction sites in the urban area was introduced in case studies. In addition, a comparative test on the same volume of charge applied to 360g of 1 new product 1 set and 180g of the existing FlNECKER Plus 2 sets was conducted. As a result of the test, the two cases were equivalent in breaking efficiency and the level of noise and vibration, and as for the method, the working time decreased by 32%, thus, it was proven to be excellent in terms of construction.

• Polymer(Korea)
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• v.31 no.5
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• pp.410-416
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• 2007

Monodisperse polymer particles were prepared via one- step seeded polymerization using PMMA as seed particles, and HDDA, triEGDMA or EGDMA as crosslinking monomer. For the study, the effects of 1) the ratio of the absorbed monomer to the seed polymer particles (swelling ratio), 2) the characteristics of crosslinking monomer, 3) electroless Ni plating, and 4) electroless Au Plating on the variation of mechanical properties of polymer particles, such as recovery rate, K-values, breaking strength and breaking displacement were investigated by using MCT (micro compression test). It was observed that swelling ratio of polymer particles influenced only on breaking strength of polymer Particles, while electroless plating did on recovery rate, K-values ($K_{10}\;and\;K_{20}$) and breaking strength of electroless plated polymer particles. However, breaking displacement and K-values ($K_{30}{\sim}K_{50}$) were more or less insensitive to electroless plating.