• Title, Summary, Keyword: 충격에너지

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A Study on the Effects of Oil Shocks and Energy Efficient Consumption Structure with a Bayesian DSGE Model (베이지안 동태확률일반균형모형을 이용한 유가충격 및 에너지 소비구조 전환의 효과분석)

  • Cha, Kyungsoo
    • Environmental and Resource Economics Review
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    • v.19 no.2
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    • pp.215-242
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    • 2010
  • This study constructs a bayesian neoclassical DSGE model that applies oil usage. The model includes technology shocks, oil price shocks, and shocks to energy policies as exogenous driving forces. First, this study aims to analyze the roles of these exogenous shocks in the Korean business cycle. Second, this study examines the effects of long-term changes in the energy consumption structure, including the reduction in oil use as a share of energy consumption and improvement in oil efficiency. In the case of oil price shocks, results show that these shocks exert recessionary pressure on the economy in line with those obtained in the previous literature. On the other hand, shocks to energy policies, which reduce oil consumption per capital, result in opposite consequences to oil price shocks, decreasing oil consumption. Also, counterfactual exercises show that long-term changes in the energy consumption structure would mitigate the contractionary effects of oil price shocks.

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An Experimental Study on the Absorbed Energy of Polymeric Foam According to Different Mass and Impact Velocity Based on the Constant Impact Energy (동일 에너지 조건하에 충격체 질량과 속도변화에 따른 발포 고분자의 흡수 에너지에 관한 실험적 연구)

  • Kim, Byeong-Jun;Kim, Han-Kook;Cheon, Seong S.
    • Composites Research
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    • v.27 no.2
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    • pp.42-46
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    • 2014
  • In the present study, impact tests were carried out to investigate the crashworthy behaviour of the expanded polypropylene under the constant incident energy (100 J and 200 J) with five different combinations of striker mass and velocity. Also, preliminary quasi-static test was performed to obtain basic characteristics of the expanded polypropylene. MTS 858 and Instron dynatup 9250 HV were used for the quasi-static test and impact tests, respectively. In consequence, it was found that the impact energy absorption characteristics of the expanded polypropylene was more influenced by the striker mass instead of the velocity of the striker.

Review on Shock Absorber for Spacecraft Lander (착륙선용 충격 완충장치에 대한 고찰)

  • Lee, Chun-U
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.193.2-193.2
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    • 2012
  • 달착륙선 등과 같은 특수 목적을 위해 제작된 우주용 착륙선에는 착륙 시 전달되는 충격하중이 탑재장비로 전달되지 못하도록 연착륙(soft-landing)을 위한 충격흡수 메커니즘이 구현되어 있어야 한다. 일반적으로 자동차 및 항공기에서는 실린더와 피스톤으로 구성된 유공압식 완충장치를 주로 사용하여, 피스톤 압축으로 실린더 내부 오일 또는 압축공기가 오리피스를 통하여 분출됨에 따라 유체마찰 에너지를 활용한 충격 흡수장치가 일반적이다. 그러나 이와 같은 지상 장비용 유공압식 충격흡수 메커니즘은 진공 및 무중력 우주 환경하에서 오리피스 기능 상실, 유압유 기화 현상 및 극저온/고온 환경에서의 성능저하 등의 문제점으로 인하여 우주용 착륙선 충격완충장치로 적용이 불가능하다. 따라서 기존의 우주용 착륙선의 대부분은 충격에너지를 기계적인 좌굴 소성 변형에너지로 변환하여 충격을 흡수할 수 있도록 알루미늄 허니콤을 주로 많이 사용하여 왔다. 본 연구에서는 진공 및 무중력 우주환경에서 착륙선 충격완충 장치로 적용이 가능하도록 실리콘 포옴과 스프링을 조합하여 구성하였으며, 충격완충 매체로 유압유 및 공압을 대체할 수 있도록 실리콘 포옴을 후방 사출 성형 방식으로 적용하여 오리피스를 통과한 실리콘 포옴의 변형에너지로 충격에너지를 흡수하게 함으로서 착륙 완충효율을 극대화 할 수 있도록 검토하였다.

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The impact strength properties of carbon/glass hybrid composite for wind turbine blade (풍력블레이드용 탄소/유리 하이브리드 섬유강화 복합재료의 충격 특성에 관한 연구)

  • Kim, Se-Young;Han, In-Sub;Woo, Sang-Kuk;Hong, Ki-Seok
    • 한국신재생에너지학회:학술대회논문집
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    • pp.378-381
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    • 2007
  • 탄소섬유가 중앙에 적층된 풍력발전용 블레이드 소재인 탄소 유리섬유 하이브리드 복합재료가 VARTM(Vacuum Assisted Resin Transfer Molding)공법을 이용하여 제작되었다. 아이조드 충격시험법을 이용하여 온도, 하이브리드화 비율 그리고 노치에 대한 충격강도의 영향을 연구하였다. 온도 감소 및 탄소섬유의 증가에 의해 충격강도는 감소하는 경향을 보였으며, 노치에 의해 하이브리드 복합재료는 약 $25{\sim}30$%가량의 충격강도 감소를 보였다. 그러나 단일 탄소섬유 복합재료의 경우 노치민감도는 없었으며, 이에 소량의 유리섬유 첨가로 인해 하이브리드화 하였을 경우 충격강도 향상 및 저온 충격강도 안정성을 확보 할 수 있었다.

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Characteristics of Falling Weight Impact Responses due to Stacking Sequences of CF/Epoxy Composite Plates (CF/Epoxy 복합평판의 적층구성에 따른 낙추충격특성에 관한 연구)

  • 박노식;임광희;김기형;양인영
    • Composites Research
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    • v.13 no.6
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    • pp.30-38
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    • 2000
  • In this paper, a system of falling weight impact tester was built up to evaluate the impact energy absorbing characteristics and impact strength of CFRP laminate plates in consideration of stress wave propagation theory. Delamination area of impacted specimens for the different ply orientation was measured with ultrasonic C-scanner to find correlation between impact energy and delamination area. Absorbed energy of quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the more absorbed energy. Hybrid specimen containing GFRP layer was higher than that of normal specimens.

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FFT 필터링 기법을 적용한 저에너지 충격시험기의 충격신호 분석

  • 김준영;윤성호;권상호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.29-29
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    • 1999
  • 낙하추 방식의 저에너지 충격시험기는 일정한 질량을 가진 충격체를 금속재/복합재 구조재에 낙하시켜 줌으로써 인위적인 충격에너지를 금속재/복합재 구조재에 가하여 주는 장치로서 금속재/복합재 구조재의 충격으로 인한 손상 거동과 충격특성을 평가하기 위한 용도로 널리 활용되고 있다.

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The Absorbed Energy of Carbon/Epoxy Composite Laminates Subjected to High-velocity impact in Considering the Loss of Projectile Mass (고속충격을 받는 Carbon/Epoxy 복합재 적층판의 충격체 질량손실을 고려한 흡수에너지 예측)

  • Cho, Hyun-Jun;Kim, In-Gul;Lee, Seokje;Kim, Young-A;Woo, Kyeongsik
    • Composites Research
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    • v.26 no.6
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    • pp.349-354
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    • 2013
  • In this paper, we conducted high velocity impact test for Carbon/Epoxy composite laminates and proposed advanced method for predicting the absorbed energy of composite laminates. During high-velocity impact test, we discovered loss of projectile mass macroscopically using high speed camera, thus we calculated the absorbed energy of composite laminates by taking loss of projectile mass into account. We proposed a model for predicting the absorbed energy of composite laminates subjected to high-velocity impact, the absorbed energy was classified into static energy and dynamic energy. The static energy was calculated by the quasi-static perforation equation that is related to the fiber breakage and static elastic energy. The dynamic energy can be divided by the kinetic energy of deformed specimen and fragment mass. Finally, the predicted absorbed energy considering loss of projectile mass was compared with experimental results.

A Study on the Anti-impulsive Strength of the Helmets for a Gas Industry (가스산업용 안전모의 내충격 안전성에 관한 연구)

  • Kim, Chung Kyun;Kim, Tae Whan
    • Journal of the Korean Institute of Gas
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    • v.17 no.6
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    • pp.52-57
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    • 2013
  • In this study, the strain energy density, stress and deformation behaviors have been analyzed as functions of a thickness and a force area of protective helmets with and without an extruder on the top of the shell structure using the finite element method. The strain energy density in which is related to the absorption capacity of an impact energy transfer is one of a key element of the helmet safety. The FEM analyzed results show that when the impulsive force of 4,540N is applied on the top surface of the helmets, the maximum stress is linearly reduced for an increased area of impact forces. But, the maximum strain energy density has been reduced for the increased force area. The reduced strain energy density may increase the impulsive forces transferred to the head and neck of helmet wearers, which may decrease the impact energy absorption safety of the helmets. In thus, it is safer design of the helmet in which has an extruded structure on the summit surface, but the modified helmet may decrease the impact energy absorption capacity.

Innovative impact apparatus for fiber reinforced cement composites (섬유보강 시멘트 복합재료용 충격 시험장치)

  • Kim, Dong-Joo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.403-404
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    • 2010
  • This paper introduces new impact apparatus using elastic strain energy for Fiber Reinforced Cementitious Composites [HPFRCC] which requires larger size of specimen and higher impact load and energy to fail the specimens. New impact apparatus utilize elastic strain energy to generate high rate impact stress wave and it is much smaller, cheaper and safer than current other impact devices.

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