• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1378-1381
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• 2003

Recently, high-performance composite materials have been used for various industrial fields because of their superior high strength, high stiffness and lower weight. In this study, manufactured fiber reinforced metal laminate materials are composed of two parts. One is hard-anodized A15083-O alloy as a face material and the other is high strength aramid fiber (Twaron CT709) and polyethylene fiber(Dyneema HB25) laminates as a back-up material. Resistance to penetration is determined by protection ballistic limit(V$\sub$50/, a static velocity with 50% probability for complete penetration) test method. V$\sub$50/ tests with 0$^{\circ}$ obliquity at room temperature were conducted with 5.56mm ball projectiles that were able to achieve near or complete penetration during high velocity impact tests.

• Journal of Advanced Research in Ocean Engineering
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• 제2권1호
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• pp.28-39
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• 2016

This paper provides theoretical and experimental results to verify the crashworthiness of FH32 high-strength steel for arctic marine structures against ice impact. Assuming that side-shell structures of the Korean arctic research vessel, ARAON, with ice-notation PL10, collide with sheet ice, one-third-scale test specimens with a single transverse frame are manufactured. Impact-bending tests were conducted using a rigid steel striker that mimics sheet ice. Drop height was calculated by considering the speed at which sheet ice is rammed. Prior to impact-bending tests, tensile coupon tests were conducted at various temperatures. The impact-bending tests were carried out using test specimens fully fixed to the inside bottom frame of a cold chamber. The drop-weight velocity and test specimen deformation speed were measured using a high-speed camera and digital image correlation analysis (DICA). Numerical simulations were carried out under the same conditions as the impact-bending tests. The simulation results were in agreement with the test results, and strain rate was a key factor for the accuracy of numerical simulations.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.389-390
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• 2009

최근 폭탄테러 등에 의한 건축구조물의 피해 및 2차적인 인적 물적 피해가 증가하고 있다. 따라서 본 연구에서는 고속 비상체의 충격시험에 의한 섬유보강콘크리트의 내충격 성능평가를 실시하여 내충격 성능의 향상을 위한 기초자료를 제시하는데 목적을 두고 있다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.30-31
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• 2014

Since consists of regression equation by penetration depth prediction calculated by existing NDRC formula mainly considers properties of projectile, impact velocity, compressive strength as parameter, it is difficult to apply it to fire reinforced concrete. In this study, scabbing limit thickness was predict considering fiber reinforcement effect by local fracture of concrete was evaluated through high-velocity impact test. As a result of applying fracture reduction coefficient to NDRC, it was possible to predict scabbing limit thickness of fiber reinforced concrete similarly with actual measurement.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.30-31
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• 2015

High velocity impact of projectile generate local failure such as penetration, scabbing, perforation on concrete. It has been reported that local failure is affected by such as nose shape, mass of projectile. In this study, comparing and weighing the impact failure properties of concrete by high velocity impact test that using spherical nose and flat nose type projectile. As a result, It was considered that scabbing of Flat nose projectile reduced more than spherical nose projectile by dispersion of impact force.

• 대한기계학회논문집A
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• 제41권11호
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• pp.1065-1075
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• 2017

본 연구는 고속충돌에 따른 파괴로 인하여 발생한 파편들의 분산거동을 예측하기 위해 고속충돌 실험과 함께 재료거동 모델링 및 수치해석을 수행하였다. 알루미늄 합금과 강철로 각각 구성된 2종류의 위협체 및 표적판에 대해 충돌실험을 수행하였으며 위협체는 약 1 km/s의 속력으로 표적판과 충돌하고, 이 충돌로 인하여 발생한 파편은 알루미늄 합금 관측판에 손상을 유발시키게 하였다. 사용된 소재의 차이에 의해 파편의 분산거동이 상이하였으며 이에 따라 관측판에 형성된 파편의 분산 반경 또한 다름을 확인하였다. 수치해석은 실험과 동일한 조건하에서 수행되었으며 파편으로 인한 파괴 및 손상을 모사하기 위하여 입자완화 유체동역학(smoothed particle hydrodynamics, SPH)기법과 유한요소(finite element, FE) 연계 기법을 적용하였다. 실험 측정된 결과와 해석값을 비교분석한 바, 표적판의 관통부 지름과 관측판상의 파편 분산반경은 5 % 이내의 오차로 잘 일치하였다. 아울러 강철 위협체와 강철 표적판이 충돌한 경우 가장 큰 분산반경을 보임에 따라 타 경우에 비해 가장 위협적임을 알 수 있었다.

• Computers and Concrete
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• 제22권1호
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• pp.123-132
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• 2018

Reinforced concrete (RC) columns which are the main vertical structural members are exposed to several static and dynamic effects such as earthquake and wind. However, impact loading that is sudden impulsive dynamic one is the most effective loading type acting on the RC columns. Impact load is a kind of impulsive dynamic load which is ignored in the design process of RC columns like other structural members. The behavior of reinforced concrete columns under impact loading is an area of research that is still not well understood; however, work in this area continues to be motivated by a broad range of applications. Examples include reinforced concrete structures designed to resist accidental loading scenarios such as falling rock impact; vehicle or ship collisions with buildings, bridges, or offshore facilities; and structures that are used in high-threat or high-hazard applications, such as military fortification structures or nuclear facilities. In this study, free weight falling test setup is developed to investigate the behavior effects on RC columns under impact loading. For this purpose, eight RC column test specimens with 1/3 scale are manufactured. While drop height and mass of the striker are constant, application point of impact loading, stirrup spacing and concrete compression strength are the experimental variables. The time-history of the impact force, the accelerations of two points and the displacement of columns were measured. The crack patterns of RC columns are also observed. In the light of experimental results, low-velocity impact behavior of RC columns were determined and interpreted. Besides, the finite element models of RC columns are generated using ABAQUS software. It is found out that proposed finite element model could be used for evaluation of dynamic responses of RC columns subjected to low-velocity impact load.

• Composites Research
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• 제26권4호
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• pp.223-229
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• 2013

본 연구에서는 자동차가 불규칙한 노면을 주행 시 받게 되는 충격으로 인하여 마운트 상단에 발생하는 영구변형을 방지하고자 하이브리드 복합재료를 사용한 스트럿 타워를 설계하였다. 타이어와 현가장치에서 흡수 가능한 에너지량을 초과하였을 시 잔류 충격은 마운트로 전이되며, 특히 고속주행성능을 향상시키기 위하여 강직한 현가장치를 도입한 경우, 에너지 흡수량 저하로 인하여 기존의 스트럿 타워가 쉽게 변형될 수 있다. 유한요소해석을 통하여 압연강판과 탄소섬유 복합재료로 이루어진 하이브리드 복합재료 스트럿 타워의 최적설계를 진행하였으며, 낙하충격시험을 실시하여 동적 거동을 연구하였다. 또한 3차원 형상측정과 초음파 비파괴 검사방법을 이용하여 스트럿 타워의 손상 유무를 확인하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제4권4호
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• pp.45-50
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• 2003

In order to investigate the effect of surface treatment (Anodizing) and rolling on AI 5083-H131 alloy, under hyper velocity impact, a ballistic testing was conducted. Ballistic resistance of these materials was measured by a protection ballistic limit ($V_{50}$)' a statistical velocity with 50% probability of penetration. Perforation behavior and ballistic tolerance, described by penetration modes, were respectfully observed, by $V_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with 0$^{\circ}$ obliquity at room temperature using 5.56mm ball projectiles. $V_{50}$ tests with 0$^{\circ}$ obliquity were also done with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes of Al 5052-H34 alloy were compared to those of Al 5083-H 131 alloy.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.219-231
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• 2004

The Charpy and Izod impact tests are the most prevalent techniques used to characterize the effects of high impulse loads on polymeric materials. An analysis method for rubber toughened PVC is suggested to evaluated critical dynamic strain energy release rates(G$_c$) from the Charpy impact tester was used to extract ancillary information concerning fracture parameters in additional to total fracture energies and maximum critical loads. The dynamic stress intensity factor KID was computed for varying amounts of rubber contents from the obtain maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact for PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.