• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.349-352
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• 2007

A GFRP based composite blade was developed for a 2MW wind energy conversion system of type class IIA. The blade sectional geometry was designed to have a general shell-spar and shear web structure. The load cases specified in the IEC61400-1 international specification were considered. For withstanding all relevant extreme loads, the structural analysis for the complete blade was performed using a commercial FEM code. The static load carrying capacity, blade tip deflection and natural frequencies were evaluated to satisfy the strength and stability requirements in accordance with the IEC61400-1 and GL Regulations. The prototype blade was passed the structural proof test for GL certification.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.86-92
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• 1997

When Lubricants is used under severe running condition, tribological characteristics is very important. I have studied the lubricating oil viscosity, kinds of additives and lubricating oil temperatures were changed. In order to study the effect of oil temperature on the wear of the surface, the temperature of the oil was changed for the same sample. Moreover, the temperatures of three kinds of oils which have very different viscosities at room temperature, were varied while the oil viscosity was unchanged. It was shown from the test results that wear is not greatly affected by the amount of ZnDTP antiwear agent, but E-P additives are less effective against wear than ZnDTP additives. The viscosity of lubricating oil and its tempea-ature greatly affect the wear of the surface. Combining all the wear data with those of the surface strength, it was observed that the higher the load, the lower the scratch of wear, and also in the case of the same running load, the lower the wear, the longer the life of the surface strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.355-362
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• 2015

Test procedure for the design verification of wind turbine pitch and yaw bearings has been developed. Test items were selected to evaluate operational reliability of pitch and yaw bearings by considering loading and operational conditions, and by analyzing the design criteria of pitch and yaw bearings. The developed test items consisted of preliminary test, fatigue load test, extreme load test, low temperature environmental test and dismantling inspection after all the test were completed. Because it reflects the actual operational conditions of the pitch and yaw bearings, the developed test procedure has high reliability and can verify the basic design considerations in the international standard and guidelines.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.812-819
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• 2010

Recently residential buildings are characterized with high-rise and high density. Under this circumstance, achieving comfortable and healthy indoor environment with minimized energy consumption becomes a very challenging engineering and societal issue. Along this the increased size and transparency of window as well as light surface caused by high stories lowers the heat shield efficiency of building. Since glass that constitutes building surface has low heat efficiency, it aggravates heat loss of all building considerably, thereby resulting in extreme heating load and cooling load in the country where temperature varies much in summer and winter. The research will check whether experiment can be effectively done by overcoming the limit of existing artificial solar laboratory constructed in the country and properly adjusting controlled variables with simplified function through construction of this experimental set.

• Steel and Composite Structures
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• v.27 no.2
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• pp.217-227
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• 2018

This paper utilizes 3D FEM to provide deeper insights about the structural behaviour of a 6.1 m span steel culvert, which was previously tested under extreme loading. The effect of different input parameters pertaining to the backfill soil has been investigated, where the structural response is compared to field measurements. The interface choice between the steel and soil materials was also studied. The results enabled to realize the major influence of the friction angle on the load effects. Moreover, the analyses showed some differences concerning the estimation of failure load, whereas reasons beyond this outcome were arguably presented and discussed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.239-246
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• 1999

recently there have been many destructive seismic events in Kobe Japan in 1995 and in Northridge California USA in 1994. etc. The Korean Bridge Design Standard Specifications adopted the seismic design requirements in 1992. Comparing the earthquake magnitude in Korea with those in the west coast of the USA it may be said that the current seismic design requirements of the Korean Bridge Design Standard Specifications provides too conservation design results especially for transverse reinforcement details and amount in reinforced concrete columns. This fact usually makes construction problems in concrete casting due to transverse reinforcement congestion. And the effective stiffness Ieff depends on the axial load P(Ag{{{{ {f }_{ck } }}) and the longitudinal reinforcement ratio Ast/Ag and it is conservative to use the effective stiffness Ieff than the gross section moment Ig. Seismic design for transverse reinforcement content of concrete column is considered of extreme-fiber compression strain R-factor axial load and stiffness etc.

• Wind and Structures
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• v.1 no.2
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• pp.145-160
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• 1998

In recent years, the effects of a possible climate change have been discussed in regard to wind loading on buildings and structures. Simple scenarios based on the assumption of global warming suggest an increase of storm intensities and storm frequencies and a possible re-distribution of storm tracks. Among recent publications, some papers seem to verify these scenarios while others deny the influence of climatic change. In an introductory step, the paper tries to re-examine these statements. Based on meteorological observations of a weather station in Germany, the existence of long-term trends and their statistical significance is investigated. The analysis itself is based on a refined model for the wind climate introducing a number of new basic variables. Thus, the numerical values of the design wind loads used in modern codes become more justified from the probabilistic point of view.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.191-198
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• 2019

In this paper the evaluation scheme for determining torsional irregularity of Hanok has been proposed. The proposed method can evaluate torsional irregularity of Hanok easily only with characteristics of Hanok shapes, arrangement of lateral load resisting frames and their lateral stiffness without time consuming and complicate 3-dimensional structural analysis. The proposed formula is expressed as allowable maximum eccentricity, and torsional irregularity is evaluated by comparing this value with actual eccentricity. The applicability of the proposed scheme was evaluated by applying it to the line shape plan Hanok with two symmetrically arranged walls and the result was expressed by formula and graph. The results showed that the allowable maximum eccentricity is 10% of plan dimension perpendicular to the seismic load when the walls are placed at the extreme end. The proposed formula was expressed as a generalized formula so it can be applied generally to the various plan shape and wall arrangement of Hanok.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.113-114
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• 2022

The purpose of this study is to identify the rear energy transfer amount and time delay capability of the protection panel that has been impated by a projectile and the protection panel reinforced the foam polypropylene on the rear of the fiber reinforced cement itious composites, and compared and analyzed the load resistance capacity, energy dissipation capacity, and impact delay capacity when dynamic extreme load were applied to the specimen.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.845-851
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• 2015

Load shedding is a last measure to avoid nationwide cascading collapses of power system by removing the pre-determined amount of loads from the main grid. In Korea, SPS(Special Protection System) is prepared to keep the power system stability from the extreme contingency of the critical transmission line losses. Among them, we need to pay attention to 765kV T/L’s because they have great influence on the total system stability. According to the present SPS operating guide, the total loads of 1,500MW should be removed through 2 step under-voltage load shedding(UVLS) scheme in case of 765kV T/L’s contingencies. However, it is not clear to defined how to determine the typical load reduction amounts for each case. This paper proposes a method to estimate appropriate amounts of load shed for 765kV T/L’s contingencies by analyzing the relevant national and international standards.