In this study, finite element (FE) analysis was performed to evaluate the seismic performance of the water treatment plant, which is a major state of the art water treatment plant, to predict tensile cracks and compressive failure. The FE model simulation for two facilities of the water purification plant was made considering the initial conditions, boundary conditions and water effect. For the nonlinear dynamic analysis, seismic analysis was performed using ground acceleration. Tensile cracks and compressive failure are analyzed and the effects on the structures are analyzed. As a result of the analysis, tensile cracks can be predicted to occur in the main structure.

A parametric study was carried out to gain an insight about structural performances considering abnormal behavior effects in high strength steel pipe strut system. Six load cases were considered as undesirable deflections of strut structures, which are basic load combination, excessive excavation situations, impact loading effects, additional overburden loads, load combinations, and 50% reduction of strut length. Subsequent simulation results present various influences of parameters on structural performances of the strut system. Based on the results, we propose methods to prevent unusual behaviors of pipe-type strut structures made of high strength steels.

본 연구에서는 실대형 실험과 구조해석을 통하여 현장에서 사용되는 기둥-서까래-도리, 기둥-도리-방풍벽 접합부를 적용한 강관 골조 플라스틱 연동온실의 정적 구조 성능을 분석하였다. 실대형 재하실험 결과는 접합부를 강접합으로 가정한 구조해석 결과와 비교하여 구조물의 횡방향 강성과 각 부재의 하중분담률에서 많은 차이를 보였다. 동고 높이에서 측정한 수평변위는 실험과 구조해석의 차이가 40% 이었고 수직변위는 89%의 차이를 보였다. S3 부재의 발생응력을 기준으로 한 각 부재별 하중분담률을 비교한 결과 실험과 구조해석에서 두 배 이상의 차이를 보이는 부재가 있었으며, 하부측벽이음(S2), 기둥 상부(S7) 등 주요 부재의 실험결과가 구조해석의 하중분담률을 재현하지 않았다. 현장에서 사용하는 접합부가 충분한 강성을 확보하지 않음으로써 구조물에 작용하는 외력을 각 부재에 적절하게 전달하지 못했으며 이로 인해 구조물의 강성이 저하되는 현상이 나타났다. 설계 단계에서 일반적으로 구조 해석에 의해 결정되는 구조성능의 신뢰도는 접합부의 특성을 보다 면밀하게 고려했는지 여부에 따라 좌우 될 수 있다. 따라서 온실 구조 성능에 대한 신뢰성을 높이기 위해서는 온실에 사용되는 다양한 접합부를 고려할 수 있는 구조해석 기술의 개발이 필요하며 설계 기준에서 상세 설계 방법을 보다 명확히 규정해야 할 것으로 판단된다.

Numerical analysis was performed to evaluate for reinforcing performance of RC beams in flexure strengthened with Textile Reinforced Mortar (TRM) in this study. New bond strength model for TRM based on the model proposed by Teng et al. was suggested to predict the flexural behavior of RC beams and effective stress in accordance with debonding of TRM. And reduce factor of 0.729 was suggested by investigation of results on the bending test of RC beams strengthened with TRM. Reliability of proposed bond strength model was verified through the comparisons between collected test results and predicted results about the ultimate load of RC beams occurred by debonding of TRM. The ratios of predicted results on the total experimental results, the average and coefficient of variation were 1.00 and 0.094, respectively. Also, nonlinear analysis method proposed by Cho et al. was used to predict the displacement at the cross-section of mid-span for RC beams in flexure strengthened with TRM. At the three state of the RC beams such as occurrence of initial flexural crack in tensile concrete, yield of tensile rebar, and ultimate in accordance with debonding of TRM. Displacements of beams were calculated at the three state and load-displacement curves by predicted results were compared to the collected test results.

Although most of the automobile bodies are made of steel, the application of aluminum alloy sheet with high strength is under consideration for the development of environmentally friendly lightweight body for fuel economy improvement and carbon dioxide emission reduction. In the case of some inner plates, application of magnesium alloy sheet is examined. TRB plate has been studied mainly for weight reduction and rigidity reinforcement of steel plate parts. Recently, research on aluminum TRB rolled plate for light and environment friendly automobile application has been started, It is expected that the development of eco - friendly TRB rolling material made of light alloy will increase as the importance of light weight body for future energy efficiency increases. Therefore, in this study, we tried to obtain the technology to improve the quality of the product by pre - verifying the cooling performance of the hot forming process through the heat flow analysis and evaluating the cooling performance through the temperature distribution analysis. As a result, it was found that the temperature distribution through the flow velocity problem and the flow of the cooling channel can influence the quality of the final product through different heat distribution and cooling time depending on the shape of the mold and the product.

This paper aims to reveal the effects of the K- turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- turbulence model under the different flow rate. It can be expected that the maximum temperature of K- turbulence model is corrected by using the average error rate without the result of K- turbulence model.

Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear in fishing operation is generally related to hydrodynamic resistance on the gear. This research is to propose a low drag generated midwater trawl in terms of the gear design improvement using simulations. The results from the simulation were verified with results that mirrored the model experiments. From the results, the resistance force of the proposed gear decreased to 29% compared to that of the current gear. Furthermore, the gear performance also improved with increased gear mouth compared to the current one. Therefore, the proposed gear will be helpful to reduce the greenhouse gases from fishing operation. It will also contribute to the fishing industry by saving fuel.

In this study, a numerical approach for automotive louvered fin heat exchanger is carried out to investigate the effect of louvered angle on the heat transfer characteristics. The numerical simulation code STAR-CCM+ is utilized to calculate flow and temperature fields with polyhedral meshes. The results show that the flow efficiency is increased as the louver angle is high. Also, the outlet temperatures are nearly the same according to louver angles because the average Nusselt numbers are nearly equivalent regardless of louver angle.

In this study, finite element analysis of korean precast concrete panels was performed and 3D infinite element modeling was used. Infinite elements can be formulated in time domain and nonlinear behavior analysis is possible. Based on the numerical results, the performance of the packing layer of korean precast concrete panels was examined.

This study investigates the flexural shear strength of ultra high performance concrete I-girder. The effect of aspect ratio on the flexural - shear strength of UHPC was analyzed using finite element analysis. The UHPC I-type girder was modeled using 3D shell elements and analyzed using geometric and material nonlinear analysis. The boundary condition is simple support condition and a displacement load is applied to the center of the upper flange. The results shows that shear strength decreased as the aspect ratio increased and the bending-shear failure of UHPC I-girder does not occur even at larger moment than ordinary concrete due to the cross-linking action of steel fiber.

본 연구에서는 연륙연도 사업에 대응하는 경제성 및 안정성을 갖춘 쌍동선형 차도선의 개발을 위해 U형과 V형의 서로 다른 쌍 동선형을 CFD 해석을 수행하여 저항성능을 비교하였다. CFD 해석 결과 U형 쌍동선형의 경우 14kts 이상의 고속에서 선수부 파형에 이상 이 발생하여 정상적인 운행이 불가능하다 판단되었으며, 이에 비해 V형은 동일한 속도에서도 이상이 발생하지 않았으며, 또한 U형 쌍동선 형 대비 V형 쌍동선형의 경우, 저속에서는 U형 대비 높은 침수표면적에도 불구하고 거의 같은 RTS값을 보이지만, 고속으로 넘어가면 U형 에 비해 확연히 낮은 RTS값을 보임을 확인, V형의 쌍동선형이 U형에 비해 저항성능이 개선됨을 확인하였다.

This paper aims to reveal the effects of the K-ε turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- ε turbulence model under the different flow rate. It was found that there was no need to apply K-ε turbulence model when the flow rate is over 500m3/h because the difference of maximum temperature is under the 6℃.

In fire design for floors, the three criteria of stability, integrity and insulation are required for the specified fire resistance duration. Among these, stability is not easy to confirm. For solid prestressed concrete slabs of uniform thickness, Eurocode 2 provides tabulated data and specifies an axis distance to the centroid of strands to achieve particular fire resistance ratings, but it is not clear if this data can be used for a wide range of different prestressed slab profiles. In order to verify the current code-fire ratings for precast prestressed slabs, both simple and advanced calculation methods are investigated. This paper examines the use of calculation methods, accounting for the real behaviour of unprotected simply supported prestressed concrete slabs exposed to the standard ISO 834 fire. The calculated fire resistance of each prestressed concrete slab is compared with tabulated data in Eurocode part 1.2, with detailed discussion.