• 건축구조
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• v.13 no.3
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• pp.106-107
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• 2006

달걀낙하시험시 사용되었던 안정한 형태에서 아이디어를 얻어 구조물의 형상을 결정하게 되었다. 사이트의 가장 큰 특징인 수변공간을 유지하는 동시에 활용하는 방안으로 띄운 구조를 적용하였다. 리조트 시설인 공간의 특성에 따라 대공간구조를 사용하여 긴 스팬을 최대한 이용하는 반면 지반에 전달되는 연직하중을 최소한으로 하고자 하였다. 이 구조물은 서울이라는 거대한 도심의 중심에 위치하는 휴식공간인 동시에 랜드마크가 될 것이다.

• Explosives and Blasting
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• v.22 no.3
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• pp.43-55
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• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2001.05a
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• pp.453-456
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• 2001

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.77-82
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• 2015

Slamming means that the hull hits the waves and receives impact pressure. This slamming effect may cause harm to people and when you put the hull at risk. so it is very harmful for cargo safety. Therefor slamming impact pressure should be fully considered in ship designing. In this study the model of wedged type structure are produced aimed to simulate a free fall that the experiments were carried out on different weight and free fall height. The flow field has been obtained by 2-frame grey level cross correlation PIV(Particle Image Velocimetry) method and experiment was divided into water entry and water exit. The impact pressure of free fall structure by a pressure acquisition system apply to dewetron system. The angles between a model and the water surface are adapted $15^{\circ}$ respectively. The weight change of models was given as 1.5, 1.8 and 2.0kg. To study slamming phenomenon for free fall height the experiments were carried out by the free fall height of 100, 200 and 300mm. The experimental value of the impact pressure according to the changes in weight was increase impact pressure in proportion to the increase in weight and higher free falling height has also influenced the increase in impact pressures.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.493-499
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• 2013

This paper presents are experimental investigation to figure out impact pressure and flow characteristics of a wedge type structure in free fall. The flow field has been obtained by 2-frame grey level cross correlation PIV(Particle Image Velocimetry) method, the impact pressure of free fall structure by a pressure acquisition system apply to Dewetron system. The angles between a model and the free surface are adapted $15^{\circ}$, $25^{\circ}$, $35^{\circ}$ and $45^{\circ}$ respectively. Velocity field of water exit has higher better than water entry. The impact pressure under the bottom of the model has been appeared higher values at $15^{\circ}$ than $45^{\circ}$, and also at P1.

• Water for future
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• v.29 no.1
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• pp.213-220
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• 1996

This paper presents an experimental study on the discharge head of Cherepnov water lifter that was continuously operated with the aid of the siphon. The energy used by the Cherepnov water lifter is derived from the potential energy ofthe water itself. The lifter consists of three interconnected tanks and five pipes, one of which is open and two others are hermetically sealed. The effects of varying operating parameters such as the tank and pipe size, the ratio between head of discharge and drop height were analyzed. As a result, factors that can maximize the efficiency and increase the average delivery rate were indentified. When the ratio between head of discharge and drop height is about 0.5, the efficiency of Cherepnov water lifter is maximized. In order to design the efficient Cherepnov water lifter, the discharge head of the Cherepnov water lifter should be assigned to be twice as much as the drop height. The effect of tank size on the efficiency is less than 5%, while the effect of the pipe size is not negligible. The larger the pipe size is, the more the efficiency increases.

• Explosives and Blasting
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• v.26 no.1
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• pp.15-21
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• 2008

In case of estimating the shocking vibration during the blasting demolitions, the weight and falling height of the structure, that is a potential energy, had been considered. But, this study presented a new equation which used the impulse concerning a falling weight instead of potential energy as a method of predicting the shock vibration. In this experiment, the data of the impulse were compared with the data of the potential energy by performing the free-fall, and all data were comparatively analyzed by the regression analysis method. Also, the method of the superposition theory, which is calculated by the diminution ratio according to distance, the free-fall difference according to height, and the time giving the shock to the ground according to the breakdown pattern, was compared with the previous vibration data occurring from the blasting demolitions in the same conditions. As a result, this study suggests that the impulse and the method of superposition theory be applied as a method of predicting the shocking vibration. Therefore, these results could be expected to estimate the shocking vibration more accurately than the previous method.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.233-240
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• 2017

Subsea structures are always vulnerable to accidental risks induced by fishing gear, dropped objects, etc. This paper presents the design of a subsea manifold protective structure that protects against dropped object impacts. Probable dropped object scenarios were established considering the shapes and masses of the dropped objects. A design layout for the manifold protective structure was proposed, with detailed scantlings and material specifications. A method applicable to the pipelines specified in DNV-RP-F107(DNV, 2010) was applied to calculate the annual probabilities of dropped objects hitting the subsea manifold. Nonlinear finite element analyses provided the structural consequences due to the dropped object impacts such as the maximum deflections of the protective structure and the local fracture occurrences. A user-subroutine to implement the three-dimensional fracture strain surface was used to determine whether local fractures occur. The proposed protective structure was shown to withstand the dropped object impact loads in terms of the maximum deflections, even though local fractures could induce accelerated corrosion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.75-81
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• 2005

Jettison, grid and CTS test are widely used for the store and stage separation studies. This is an introductory paper on the experimental methodology and typical results of grid and CTS test used for the Korean 3-stage sounding rocket development. Thirteen separation trajectories were evaluated in the ONERA S2MA wind tunnel at Mach numbers of 2.0 and 2.8. The test result was applied as the basic database for the design of optimized separation device.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.191-196
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• 2004

Most of studies for landing gear have been performed to analyze the shock absorbing characteristics of oleo-pneumatic struts. But it is not easy to solve the dynamic specific properties of spring type composite landing gear using a present method. The shock absorbing abilities of oleo-pneumatic landing gear strut are under influence of the internal design method on the strut rather than the landing gear structure itself. Unlike oleo type, spring type composite strut absorbs the shock with structural strength and dynamic characteristics of the strut's material and shape. The tests and analysis for the shock absorbing rate and dynamic behavior of the spring type composite fixed landing gear for 4 seats small aircraft, have been performed using landing gear drop test rig.