• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.1-10
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• 2016

This study analyzes the fabric skin of a wind turbine blade. The fabric skin is a membrane structure that was analyzed using a static Fluid Structure Interaction (FSI) method. For this study the blade of large 5 MW wind turbine was selected. In order to examine the validity of the analysis, a variety of reference data were used. Before conducting static FSI analysis, a Computational Fluid Dynamics (CFD) analysis and modal analysis were done. Then interaction analysis was conducted. FSI analysis was done with imported Aerodynamic data that resulted from the CFD analysis. The resulting observations about the membrane structure, inherent tensions, deformation of the final structure, and aerodynamic forces caused by deformation are reported.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.2
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• pp.181-192
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• 2001

이 논문은 샌드위치식 강-콘크리트 복합구조체에서 상하 강판과 격벽으로 구성되는 셀의 형상비가 거동과 성능에 미치는 영향을 다루었다. 이 구조체에서 셀 형상비는 하중전달 메카니즘과 하중분배능력을 변화시킨다. 따라서 셀 형상비에 따라 부재의 응력수준과 하중저항능력이 변화한다. 이 연구에서는 셀 형상비가 이 구조체의 거동과 성능에 미치는 영향을 규명하기 위해, 두 종류의 샌드위치식 복합구조체에 대해 다양한 셀 형상비를 설정하여 비선형 구조해석을 수행하였다. 해석결과로부터 셀 형상비에 따른 하중전달 메카니즘과 부채 응력에서의 차이점을 도출하였으며, 이들 차이점을 바탕으로 셀 형상비가 전단성능, 휨성능, 하중저항성능에 미치는 영향을 분석하였고, 파괴모드와 연성에 미치는 영향에 대해서도 간략히 언급하였다. 연구결과, 셀 형상비가 증가함에 따라 하부 강판과 콘크리트의 응력수준이 낮아지는 결과를 나타내었다. 이것은 각 부재의 유효휨강성과 유효전단강성 증가를 나타내며, 따라서 구조체의 하중저항성능도 향상되는 것으로 판단된다. 특히 셀 형상비의 증가에 따른 성능향상에서 전단성능이 휨성능에 비해 더 큰 효과를 나타내며, 이러한 차이는 파괴모드와 연성에도 영향을 미칠 것으로 판단된다. 즉, 셀 형상비가 증가함에 따라 구조물의 거동 및 파괴모드는 점차적으로 전단에서 휨으로 변화하고, 이에 따라 구조물의 연성도 점차적으로 향상될 것으로 판단된다.

• Computational Structural Engineering
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• v.20 no.4
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• pp.7-18
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• 2007

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.283-288
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• 2011

For the earthquake resistance design designer should provide that structural yielding process is principally designed with the ductile failure mechanism. In order to get the ductile failure mechanism for typical bridges, pier columns yielding should occur before that of connections. However domestic bridge design with unnecessary stiff substructure leads to unnecessary seismic loads and makes it difficult to get the ductile failure mechanism. Such a problem arises from the situation that earthquake resistant design is not carried out in the preliminary design step. In this study a typical bridge is selected as an analysis bridge and design strengths for connections and pier columns are determined in the preliminary design step by carrying out earthquake resistant design. It is shown through this procedure that it is possible to get the ductile failure mechanism with structural members determined by other design.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.578-588
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• 2002

An experimental study was conducted to investigate the effectiveness of transverse reinforcement in reinforced concrete tied columns subjected to monotonically increasing axial compression. Eighteen large-scale columns(260$\times$260$\times$1200 mm) were tested. Effects of main variables such as the concrete compressive strength, the tie configuration, the transverse reinforcement ratio, the tie spacing, and the spatting of the concrete cover were considered. High-strength concrete columns under concentric axial loads show extremely brittle behavior unless the columns are confined with transverse reinforcement that can provide sufficiently high lateral confinement pressure There is a consistent decrease in deformability of column specimen with increasing concrete strength. Test results were compared with the previous confinement model such as modified Kent-Park, Sheikh-Uzumeri, Mander, and Saatcioglu-Razvi model. The comparison indicates that many previous models for confined concrete overestimate or underestimate the ductility of confined concrete.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.47-56
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• 2008

This study was performed to evaluate the effect of Response modification factors (R-factor) in 3-, 9- and 20- story steel Moment Resisting Frame (MRF) buildings. Each structure was designed using a R-factor of 8, as tabulated in the 2000 International Building Code provision (IBC 2000) and Korea Building Code (KBC) 2008. In order to evaluate the maximum and minimum performance expected for such structures, an upper bound and lower bound design were adopted for each model. Next, each analytical model was designed using different R-factors (8, 9, 10, 11, 12) and four different structural periods with the original fundamental period. For a detailed case study, a total of 150 analytical models were subjected to 20 ground motions representing a hazard level with a 2% probability of being exceeded in 50 years. In order to evaluate the performance of the structures, static push-over and non-linear time history analysis (NTHA) were performed, and displacement ductility demand was investigated to consider the ductility capacity of the structures. The results show that the dynamic behaviors for the 3- and 9-story buildings are relatively stable and conservative, while the 20-story buildings show a large displacement ductility demand due to dynamic instability factors. (e.g. P-delta effect and high mode effect)

• Journal of Energy Engineering
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• v.29 no.3
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• pp.97-102
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• 2020

In this study, one-way fluid structure interaction analysis was adapted to verify the durability of the outdoor evacuation stair structure operated in the event of a fire when wind pressure caused by a typhoon was applied. To this end, flow analysis was performed with the flow field around the structure of the evacuation stair in a steady state, and the durability was analyzed through structural analysis such as structural stress, deformation, and fatigue life using these analysis results by fluid data input data for structural analysis. As a result of flow numerical analysis, the air flow was different according to the shape of the evacuation stair structure, and this flow velocity distribution generated by the total pressure on the structure surface. Through the structural analysis results calculated by this total pressure, the safety factor calculated as the maximum stress value was found to be more than the safety factor, and durability was proven by fatigue life and deformation analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.29-37
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• 2004

The overstrength factor and the ductility factor are the two important factors that determine response modification factors used in current seismic codes, In this paper the overstrength and ductility factors of special concentric braced frames are determined by performing pushover analysis of model structures with various stories and span lengths. and by using those factors the response modification factors are obtained. According to the analysis results. the overstrength and the ductility factors are larger than the values proposed by the codes in low-rise structures. and the opposite is true in medium to high-rise structures, It is also found that the factors increase as the height of structures decreases and the span length increases.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.133-136
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• 2008

Moment redistribution problem that reflects plasticity concept is foundation of limit state design and it has been interested to design engineers and researchers for a long time, because it enables the reasonable estimation of strength of structures through amount of reinforcement control about negative moment in support. Many researchers find that moment redistribution closely related to ductility of degree of structure and there are a lot of difficulties in achieving the reliable experimental results because of a lot of restriction of experiment. So, studies are achieved for indirect estimate methods about ductility ability of structures. Each design standards limits that the degree of redistribution of bending moment is based on the measurement of ductility of structure, and it shows conservative results. In this study, with these results, present the basic data for reasonable strength estimation methods and allowed moment redistribution of reinforced concrete continuous beams.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.113-121
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• 2015

Building using masonry accounts for most of the smaller houses in Korea but due to brittle behavior and low ductility the frequency of usage has decreased in recent years. Despite this, this form of building has been gaining attention overseas for its low cost in construction and environment-friendliness of the materials. As such, many studies are being conducted to resolve the disadvantages in structure. This study produced an specimen for masonry-filled wall and the intersection to confirm the difference in structural movement depends on the existence or lack of expansion joint and verified the reinforcement effect from inserting a connecting steel item (steel plate, stainless steel twist bar). The experiment results show that the specimen with a steel plate inserted saw an increase in durability and an improvement in the strength of the specimens, while the specimen that had stainless steel twists bar inserted saw an increase in ductility that did not cause brittle failure, indicating that the reinforcement effects of inserting a connecting steel item are effective.