• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.33-47
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• 2001

성능에 기초한 내진설계에서는 구조물이 보유하고 있는 능력을 효과적으로 파악하기 위해서 비선형 정적 해석이 적용되고 있다. 그러나 비선형 정적해석은 고차모드에 대한 효과를 고려하지 못함으로써 고층구조물이나 비정형 구조물과 같은 경우에는 정확한 비선형 지진응답의 산정과 내진성능을 평가하는데 문제점을 가지고 있다. 본 연구에서는 건축구조물의 선형 및 비선형 지진응답 평가를 위하여 응답 스펙트럼해석을 통하여 얻어지는 층전단력으로부터 층하중을 산정하는 유사동적해석법이 적용되었다. 제안된 방법을 비선형 정적 해석에 적용하여 구조물의 비선형 자동응답을 비선형 시간이력해석의 결과와 비교하였다. 기존의 층분포하중에 의한 비선형 지진응답과 비교하였으며, 제안된 방법에 의한 지진 응답이 구조물의 비선형 거동특성을 가장 정확하게 표현하였다. 그러므로 본 연구에서 제안된 방법을 사용하여 비선형 정적 해석을 수행한다면 비교적 명확한 건축물의 비선형 거동특성과 내진성능을 평가할 수 있을 것으로 판단된다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.404-407
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• 2010

본 논문에서는 비선형 동적 해석 프로그램인 AUTODYN을 이용해 기둥의 단면 형상의 변화에 따른 폭발 하중의 영향을 분석하였다. 먼저 폭발하중 산정의 타당성을 확인하기 위해 AUTODYN을 이용한 예제해석을 수행하였으며, 폭발하중에 의한 영향을 가장 효율적으로 확인할 수 있는 인자인 압력을 비교하였다. 이를 토대로 기둥 형상에 따른 폭발 저항 성능을 평가하기 위해 같은 단면적과 높이를 갖는 정사각형과 원형 기둥을 모델링 한 후 TNT의 양에 따른 폭발전후의 부피를 비교하였다. 해석결과를 비교해보면 정사각형기둥이 원형기둥보다 폭발에 대한 손상정도는 더 크지만 기둥이 절단되지 않도록 하는 저항성능이 더 우수한 것을 확인할 수 있었다. 비록 철근의 영향을 고려하지 않았지만, 이와 같은 결과를 통해 TNT의 양에 따른 기본적인 폭발거동과 대테러 설계를 위한 기둥 단면 선택시 기초적인 자료로 활용가능 할 것으로 사료된다.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.519-530
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• 1998

In this paper, the basic study on the design of the flexible keel of the energy-storage prosthetic foot was performed in order to Improve the walking performance and Increase the activities of the below knee amputees. Based on the analysis of the anthropometric data and the normal gait on two dimensional sagittal plane available In the literature, we presented a model of the basic structure of the flexible keel of the prosthetic foot. The model of the basic structure was composed of the simple beams, and linear rotational spring and damper. Laminated carbon fiber-reinforced composites were selected as the material of the basic structure model of the flexible keel In order to apply the high strength and light weight materials to the basic structure of the flexible keel of the prosthetic foot. The recoverable strain energy In response to the change of beam shape was calculated bur the finite element analysis and it was suggested that the change of beam shape could be the design variable in flexible keel design. The simulation process was systematically designed by using orthogonal array table in order to design the flexible keel structure which could store the more recoverable strain energy. finite element analysis was carried but according to the design of simulations by using the finite element program ABAQUS and the flexible keel structure of the energy-storage prosthetic foot was obtained from the analysis of variance(ANOVA). The dynamic simulation model of the prosthetic walking using the flexible keel structure was made and the dynamic analysis was carried but during one walk cycle. Based on the above results, an effective design process was presented for the development of the prosthetic fool system.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.63-69
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• 2003

In this study seismic design procedure for buckling-restrained braced frame systems was proposed using hysteretic energy spectrum and accumulated ductility spectrum constructed from single degree of freedom systems. The hysteretic energy spectra and accumulated ductility spectra corresponding to target ductility ratio were constructed first. The cross-sectional area of braces required to meet a given target displacement was obtained by equating the hysteretic energy demand to the accumulated plastic energy dissipated by braces. Twenty earthquake records were utilized to construct the spectra and to verify the validity of the design procedure. According to analysis results of three- and eight-story buckling-restrained braced frame structures designed using the proposed method, the mean values for the top story displacement correspond well with the given performance target displacements. Also, the inter-story drifts turned out to be relatively uniform over the structure height, which is desirable because uniform inter-story drifts indicate uniform damage distribution. Therefore if was concluded that the proposed energy-based method could be a reliable alternative to conventional strength-based design procedure for structures with buckling-restrained braces.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.483-491
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• 2008

There has been much focus on the strong axis steel moment connections after the Northridge earthquake in 1994. However, research studieson the seismic behavior of weak axis moment connections could be hardly found despite the fact that these connection details have been frequently used as seismic details of MRF in Korea. Therefore, the objective of this research is to provide better knowledge on the seismic behavior of weak-axis steel moment connections, which can be widely applicable to many structures with similar characteristics. For this purpose, an experimental program was designed and performed with twotypes of weak-axis steel moment connections, namely the bracket type and WUF-B type, based on the survey of existing field data and literatures. Using the experimental results obtained from the quasi-static cyclic testing of these specimens, structural performances of the joints such as hysteretic curves, maximum strength capacities and the strain of reinforced bars were investigated. From the test results, the bracket-type connection was shown to have more than a 5% story drift capacity, compared with the WUF-B type connection's 4%. These specimens were also shown to have higher strength capacities than the nominal design strength. The bracket-type connection showed a slow strength degradation after maximum strength was researched. However,the WUF-B type connection showed a rapid strength degradation that caused brittle behavior.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.455-464
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• 2013

If North Korea continuously remains an isolated nation without social interaction with South Korea, the gaps in the theoretical and technological status in construction technology become greater between North and South Korea. Therefore if interactions between North and South Korea can be made, there will be significant improvement in infrastructure technological performance can be made(i.e., Reinforced Concrete bridges). This study was performed to compare and analyze data related to the design standards of North Korean RC bridges and to execute a structural analysis based on standard design specifications of RC slab bridges. Especially, basic study of analyzing the influences on design truck loads of North and South Korea was conducted for the purpose of predicting the performance of North Korean RC slab bridges and the safety levels of traveling vehicles in advance. It is expected that the results of this study can be used as fundamental data for the set-up of South-North RC bridge specification when South and North Korea enter a stage of cooperation and interaction between South and North Korea are actively pursued to prepare for reunification.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.675-676
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• 2011

To improve efficiency and allowable life of gas turbine, the proper cooling techniques are needed. It is required not only the basic research of variable cooling techniques but also analysis of real operating conditions when design the cooling system. From this analytical results, we can predict the thermal stress and allowable life. This design process is thermal design techniques that is the most foundational design techniques to improve the efficiency of gas turbine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.437-438
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• 2008

To improve efficiency and allowable life of gas turbine and ram jet, the proper cooling techniques are needed. It is required not only the basic research of variable cooling techniques but also analysis of real operating conditions when we design the cooling system. From the present experimental and analytical results, we can predict the thermal stress and allowable life. This design process is for a thermal design technique that is the most foundational design technique to improve the efficiency of gas turbines and ram jets

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.440-447
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• 2020

The demand for large-scale horticultural complexes utilizing reclaimed lands is increasing, and one of the pending issues for the construction of large-scale facilities is to establish foundation design criteria. In this paper, we tried to review previous studies on the method of reinforcing the foundation of soft ground. Target construction methods are spiral piles, wood piles, crushed stone piles and PF (point foundation) method. In order to evaluate the performance according to the basic construction method, pull-out resistance, bearing capacity, and settlement amount were measured. At the same diameter, pull-out resistance increased with increasing penetration depth. Simplified comparison is difficult due to the difference in reinforcement method, diameter, and penetration depth, but it showed high bearing capacity in the order of crushed stone pile, PF method, and wood pile foundation. In the case of wood piles, the increase in uplift resistance was different depending on the slenderness ratio. Wood, crushed stone pile and PF construction methods, which are foundation reinforcement works with a bearing capacity of 105 kN/㎡ to 826 kN/㎡, are considered sufficient methods to be applied to the greenhouse foundation. There was a limitation in grasping the consistent trend of each foundation reinforcement method through existing studies. If these data are supplemented through additional empirical tests, it is judged that a basic design guideline that can satisfy the structure and economic efficiency of the greenhouse can be presented.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.147-152
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• 2002

본 연구에서는 검증된 Bench급 석탄 가스화 공정에 대하여 개발된 동적모사 프로그램을 중잔유 가스화 공정 모델에 적용하여 가스화 성능에 크게 영향을 미치는 주요변수, 즉 시료 투입비, 산소 공급비, steam 공급비 및 압력조절밸브 열림궤도의 영향을 파악하고, 공정변수들의 동특성을 해석하였다. 가스화기의 부하변동에 따른 주요 공정 변수들의 변동경향 및 시상수에 대한 신뢰성 있는 모사결과를 얻을 수 있었으며, 개발된 모델을 사용하여 중잔유 가스화 공정설계를 위한 기초 자료를 마련하였다.