• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.322-325
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• 2005

TTX(Tilting Train eXpress) is being designed for improving the speed of conventional railway. The purpose of this study is to evaluate energy absorbing capacity and driver's survivability for a design candidate of the front end structure of TTX. A FE model with honeycomb block, under frame, and body frame is generated for crash simulation. Based on a level-crossing accident scenario, numerical simulation is performed using LS-DYNA. The results of crash analysis show that strength improvement of the current front end structure design candidate is needed to ensure driver safety.

• 한국정밀공학회지
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• 제17권12호
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• pp.129-136
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• 2000

In the frontal collision the spot welded hat-shaped section side member is the fundamental structure for automobiles and has a great amount of absorbing capacity. For this reason LS-DYNA3D has been used for analyzing impact collapse characteristics on hat shaped section member with respect to the valuables; thickness, width ratio and spot weld potch on impact load(7.19m/sec, 1034J). By comparing the results from simulation and the experimental results, the utilization of simulation has been certified.

• 한국토양비료학회지
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• 제8권3호
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• pp.113-119
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• 1975

Volcanic Ash Soils are widely distributed in Jeju island, and constitute the important upland soils which are either presently being cultivated or are suitable for reclaiming. The characteristics of Volcanic Ash Soils according to data made available by previous studies in Jeju and the outside of the country are as following: The most conspicuous mineralogical property is the presence of amorphous mineral colloids. The colloids have large and highly reactive surface to which the common physical and chemical properties are related. Soils are low in bulk density and higher both in porosity and permeability. Accumulation of humus in the upper part of soil is found in great quantity. Cation exchange capacity is high mainly due to high humus content, but the absorbing intensity of ammonium and potassium is weaker than that of crystalline clays. The phosphate absorption coefficient is extremely high and deficiency of minor element may occur both crops and animals. Soils are densely populated with actinomycetes and anaerobic bacteria. Nitrification and activity of urease are distinctly stronger than that of non-Volcanic Ash Soils.

• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.51-56
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• 1997

Laves상 $ZrV_2$합금은 다량의 수소를 저장하지만 수소와의 결합력이 강하여 Ni-MH전지의 전극으로는 부적당하다. 전극에 응용하기 위해 $ZrV_2$합금중의 V의 일부를 Ni로 치환하여 수소와의 결합력을 약하게 하였다. 이와 같은 Zr-V-Ni계 합금에 대해 전기화학적 성질, 전극의 평형전위로부터 합금중의 수소의 열역학적성질 및 2차전지전극에의 응용가능성을 조사하였다.

• Journal of Mechanical Science and Technology
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• 제16권1호
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• pp.32-38
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• 2002

The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members (hat and double hat section, nembers of vehicles) which possess the greatest energy absorbing capacity In an axial impact collapse. This study also suggests how the collapse load and deformation mode are obtained under impact. In the program system presented in this study, an explicit finite element code, LS-DY7A3D, is adopted for simulating complicated collapse behavior of the hat and double hat shaped section members with respect to section dimensions and spot weld pitches. Comparing the results with experiments, the simulation has been verified under a velocity of 7.19 m/sec (impact energy of 1034J)

• Journal of Mechanical Science and Technology
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• 제15권2호
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• pp.180-191
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• 2001

The widely used spot welded sections of automobiles(hat and double hat shaped section members) absorb most of the energy in a front-end collision. The sections were tested with respect to axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thicknesses, width ratios and spot weld pitches on the flange were tested at high impact velocity(7.19m/sec and 7.94m/sec) which simulates an actual car crash. Characteristics of collapse have been reviewed and structures for optimal energy absorbing capacity is suggested.

• Steel and Composite Structures
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• 제20권5호
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• pp.983-997
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• 2016

The aim of this study is to investigate the impact behavior and impact-induced damage of sandwich composites made of E-glass/epoxy face sheets and PVC foam. The studies were carried out on square flat and curved sandwich panels with two different radius of curvatures. Impact tests were performed under impact energies of 10 J, 25 J and 80 J using an instrumented drop-weight machine. Contact force and displacement versus time and contact force- displacement graphs of sandwich panels were presented to determine the panel response. Through these graphs, the energy absorbing capacity of the sandwich panels was determined. The impact responses and failure modes of flat and curved sandwich panels were compared and the effect of curvature on sandwich composite panel was demonstrated. Testing has shown that the maximum contact force decrease while displacement increases with increasing of panel curvature and curved panels exhibits mixed failure mode, with cylindrical and cone cracking.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.604-608
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• 2010

This paper proposed a new 2D multibody dynamic modeling technique to analyze overriding behavior taking place during train collision. This dynamic model is composed of nonlinear spring, damper and mass by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model of rollingstock, collision energy absorption capacity, acceleration of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we choose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3D finite element analysis, and established a 2D multibody dynamic model. This 2D dynamic model was suggested to describe the collision behavior of 3D Virtual Testing Model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.246-251
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• 2003

This paper presents an experimental study on the energy dissipation characteristics of viscous damping wall (VDW). VDW is consisted of a plate floating in a thin case made of steel plated filled with highly viscous silicone oil. Because VDW demonstrates both viscous damping and stiffness characteristics, the viscous resisting force can be expressed as the sum of velocity dependant viscous damping force and displacement dependant restoring force. The viscous resisting force and energy absorbing capacity can be easily adjusted by changing three factors, i.e. viscosity of the fluid, gap distance and area of the wall plates. VDW was tested using a series of harmonic (sinusoidal) displacement history having different frequency and amplitude and the force-displacement relationship was recorded. The relationship between dissipated energy with three factors and the influence of exciting frequency on resisting force were Investigated

• 태양에너지
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• 제5권2호
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• pp.60-69
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• 1985

A low cost batch type solar heaters (capacity 200 litres) comprising horizontal tanks, which performs the dual function of absorbing heat and storing the heated water, have been designed and fabricated for the purpose of side-by-side testing. Experimental results have indicated that the sufficient hot water can be obtained in the early morning if the glazing is aided by a reflector/insulation cover. The water heater with best thermal performance such as type B supplied water at a maximum mean temperature of $46-49^{\circ}C$ in the summer afternoon and the temperature of $36-39^{\circ}C$ can be obtained in the early morning if insulation cover is used during night time. The equation has been developed for the prediction of hourly variation of the water temperature in the tank.