• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.276-279
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• 2008

In order to measure sound transmission loss (STL) of a shipboard window of small size, a special partition is built into the test opening between two reverberation rooms and the specimen is placed in that partition. For high sound insulation, the filler wall often has multi-layered structure such as double-brick wall or buckhead structure with thick steel plate, absorptive material, and sandwich panels. This paper discusses the installation method of a multi-layered filler wall that consist of gypsum boards, lead plates, and glass wool. The experimental results of various wall structures are introduced. The comparison between the results show that the sound bridge effect plays a significant role in lowering the maximum STL of the filler wall. It is also found that the higher the sound insulation performance of the filler wall is, the more important the franking transmission through other side wall of the test facility is.

• Steel and Composite Structures
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• 제14권6호
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• pp.587-604
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• 2013

There are few technical documents regulated structural performance and engineering criteria in domestic market for Structural insulated panels in Korea. This paper was focused to identify fundamental performance under monotonic loading and cyclic loading for SIPs in shear wall application. Load-displacement responses of total twelve test specimens were recorded based on shear stiffness, strength, ultimate load and displacement. Finally energy dissipation of each specimen was analyzed respectively. Monotonic test results showed that ultimate load was 44.3 kN, allowable shear load was 6.1 kN/m, shear stiffness was 1.2 MN/m, and ductility ratio was 3.6. Cyclic test was conducted by two kinds of specimens: single panel and double panels. Cyclic loading results, which were equivalent to monotonic loading results, showed that ultimate load was 45.4 kN, allowable shear load was 6.3 kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. Based on results of structural performance test, it was recommended that the allowable shear load for panels should be 6.1 kN/m at least.

• 한국항공우주학회지
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• 제36권10호
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• pp.969-978
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• 2008

선형 캐스케이드 실험장치에서 블레이드간에 주기조건을 만족하면서 적은 개수의 블레이드를 적용하는 것은 실험의 정확도 향상뿐만 아니라 실험수행에 여러 장점을 제공한다. 따라서 본 연구에서는 유로를 캐스케이드 피치의 두 배 넓이로 설정하고 두 개의 블레이드만을 설치하였을 때 주기조건이 얻어지도록 하는 벽면의 형상설계에 관한 연구를 수행하였다. 이를 위하여 주기조건에서 얻어진 블레이드 표면에서의 마하수와 동일한 결과가 얻어지도록 목적함수를 설정하였으며, 설계변수로는 벽면의 형상과 관련이 있는 12개의 변수를 선정하였다. 벽면의 설계를 위하여 기울기 기반의 최적화법을 사용하였으며, 목적함수에 민감한 변화를 나타내는 영역의 조정과 가중치를 사용하였다. 이러한 방식으로 얻어진 결과에서 주기조건과 동일한 유동특성이 얻어질 수 있음을 확인하였다.

• 한국해양공학회지
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• 제29권1호
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• pp.62-69
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• 2015

Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.

• 대한기계학회논문집
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• 제7권4호
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• pp.361-371
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• 1983

The turbulent structures of the free plane jet and two dimensional impinging jet are investigated experimentally. In order to get the two dimensional jet, the contour of the cubic equation suggested by Morel is used for a contracting nozzle. A linearized constant-temperature hot-wire anemometer is used for measurement. Mean velocities and turbulent intensities are measured along the centerline of the jet. Jet halp width spatial double velocity correlation coefficients and integral length scales are obtained. It is established that the free plane jet is truly self-preserving about 40 slot widths downstream of the nozzle. The experiments for the impinging jet are carried out at four different impingement wall locations within the self-preserving region of the free plane jet, and comparing the results with that of free plane jet, the mean velocity is changed in the region of 0.25H and turbulent intensities are affected in the region of 0.2H from the wall, respectively, where H means the distance between the nozzle exit and the wall.

• 한국진공학회지
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• 제12권4호
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• pp.281-287
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• 2003

본 연구에서는 분자동력학 방법을 사용하여 탄소 나노튜브와 같은 구조적 특성을 가정한 실리콘 나노튜브에 관한 연구를 수행하였다. 흑연판 모양의 실리콘 판에서 실리콘 나노튜브가 형성되는 활성화에너지는 매우 낮다는 것을 실리콘판 - 튜브 전이 에너지 도식도를 통하여 살펴보았다. 분자동력학 시뮬레이션 결과는 실리콘의 경우 단일벽 나노튜브가 불안정하며, 다중벽 나노튜브의 경우에 더욱 안정하다는 것을 원자결합수 및 결합각도 분포 비교를 통하여 보여주었다.

• 복합신소재구조학회 논문집
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• 제4권1호
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• pp.33-39
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• 2013

Structural insulated panels, structurally performed panels consisting of a plastic insulation bonded between two structural panel facings, are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. In Korea, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to identify fundamental performance of both monotonic load and quasi static cyclic load for SIPs in shear wall application. Static test results showed that maximum load was 44.3kN, allowable shear load was 6.1kN/m, shear stiffness was 1.23 M N/m, and ductility ratio was 3.6. Cyclic test was conducted by two kinds of specimens : single panel and double panels. Cyclic test results, which were equivalent to static test results, showed that maximum load was 45.42kN, allowable shear load was 6.3kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. From performance of structural tests, it was recommended that the allowable shear load for panels was at least 6.1kN/m.

• 한국지반신소재학회논문집
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• 제20권1호
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• pp.1-8
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• 2021

도심지에서는 공간 활용을 위해 구조물 하부 깊은 지하까지 구조물을 설치하고 있다. 그래서 구조물 건설 시, 지반에서 발생하는 토압을 방지하기 위해서 흙막이를 활용하고 있다. 굴착공사에 적용되던 흙막이가 건설기술의 발전으로 인해서 성토 공사나 옹벽 설치시에 가시설 낙석이나 산사태와 같은 위험 방지용으로도 이용되고 있다. 일반적으로 성토공사시 가시설 흙막이를 적용하는 경우는 기존에 존재하는 도로나 철도를 확장하는 경우이다. 그러므로 고속철도의 복선화 현장과 같은 성토공사에 적용되는 흙막이에 관한 연구가 필요하다. 본 연구에서는 일반적인 1열 H-pile 흙막이와 지주식 흙막이 2종류에 대해 수치해석을 하였으며, 고속철도의 단선지역에 성토하여 복선화하는 공사에 적용된 흙막이의 안정성을 분석하였다. 지주식 흙막이는 사면안정에 적용되는 억지 말뚝(이하 배면지주)을 흙막이 벽체(이하 전면지주)에 경사지게 결합한 공법이다. 분석결과, 지주식 공법은 동적하중이 적용되는 동안, 전면에만 H-plie이 설치된 타입에 비해 수평변위가 최대 19.0%만 발생하였다. 또한, 고속철의 운행속도가 느릴수록 변위가 많이 발생하였으며, 이 결과는 운행속도가 저속인 구간에서의 지반 설계시 더욱 주의가 필요하다는 것을 보여준다.

• 한국가시화정보학회지
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• 제1권2호
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• pp.38-46
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• 2003

An experimental investigation was performed to study the turbulent characteristics of swirling flow a 90$^{\circ}C$ circular tube for Re = 10,000, 15,000 and 20,000. 2D-PIV(Particle Image Velocimetry)technique was employed to measure the fluctuation velocity field. The results include spatial distributions of mean velocity vectors, turbulence intensity and turbulence kinetic energy. The axial and radial turbulence intensities, and kinetic energy profiles show double-peak structures in the inlet region of the 90 degree bend and the profiles are disappeared along the test tube with decaying the swirl intensity.

• 한국지반공학회지:지반
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• 제8권3호
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• pp.37-50
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• 1992

지진으로 인한 액상화현상은 토목구조물에 막대한 피해를 주고 있다. 본 연구에서는 액상화 현상에 대란 대책을 연구할 목적으로 모형 항만구조물을 대상으로 하여 진동대 실험을 실시하였다. 액상화현상으로 항만구조물에 발생하는 과잉변형을 방지하기 위하여 보강구간을 설치하고 그 효과에 대하여 검토하였다. 제방, 이중 널말뚝벽과 앵커 구조물의 진동대 실험을 통하여, 액상화 지반의 유동변형에 대한 특성과 보강범위에 대한 정량적 자료를 얻었다. 항만구조물을 보호하기 위한 보강구간의 범위는 진동가속도의 크기에 따라 다르다. 실험을 통하여 얻어진 구조물의 과잉변형을 보강구간의 범위와 진동가속도의 크기에 따라 나타내었다.