• 한국군사과학기술학회지
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• 제16권6호
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• pp.803-810
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• 2013

In this paper, we have verified the performance of ballistic resistance material on wet condition. Considering Korea terrain, soldiers may face many rivers and streams. However, bullet-proof jacket has no waterproofing and there's no water-proof standard in Military. Wearing wet bullet-proof jacket, soldiers can't be protected properly because of the decrement of jacket. Thus, we measure the performance of existing material on wet condition and analyze failure mechanism in order to indicate factors to improve bullet-proof jacket.

• Steel and Composite Structures
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• 제24권2호
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• pp.191-200
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• 2017

Impact resistance and weight are important features for ballistic materials. Kevlar fibres are the most widely reinforcement for military and civil systems due to its excellent impact resistance and high strength-to-weight ratio. Kevlar fibres or spectra fiber composites are used for designing personal body armour to avoid perforation. In this study, the ballistic impact behaviour of Kevlar/filled epoxy matrix is investigated. Three different fillers, nanoclay, nanocalcite and nanocarbon, were used in order to increase the ballistic impact performance of Kevlar-epoxy composite at lower weight. The filler, nanoclay and nanocalcite, content employed was 1 wt.% and 2 of the epoxy resin-hardener mixture while the nanocarbon were dispersed into the epoxy system in a 0.5%, 1% and 2% ratio in weight relating to the epoxy matrix. Specimens were produced by a hand lay-up process. The results obtained from ballistic impact experiments were discussed in terms of damage and perforation. The experimental tests revealed a number of damage mechanisms for composite laminated plates. In the ballistic impact test, it was observed whether the target was perforated completely penetrated at the back or not. The presence of small amounts of nanoclay and nanocalcite dispersed into the epoxy system improved the impact properties of the Kevlar/epoxy composites. The laminates manufactured with epoxy resin filled by 1 wt.% of nanoclay and 2 wt% nanocalcite showed the best performance in terms of ballistic performance. The addition of nanocarbon reduced ballistic performance of Kevlar-epoxy composites when compared the results obtained for laminates with 0% nanoparticles concentration.

• Composites Research
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• 제20권3호
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• pp.1-7
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• 2007

본 연구는 전단농화유체(STF)가 함침된 Kevlar 복합재료(STF-Kevlar composite)의 제조 및 방탄성능 평가에 관한 내용이다. 전단농화유체는 fumed silica와 구형 silica를 에틸렌글리콜에 혼합하여 제조하였고 이 유체를 Kevlar직물에 함침시켜 액체방탄재료를 제작하였다. 전단농화거동을 조사한 결과 사용된 STF는 모두 전단농화거동이 발현됨을 확인하였다. 그리고 방탄시험 결과 구형silica STF-Kevlar 복합재료가 보다 우수한 방탄특성을 나타내었다. 한편 방탄시험 시 neat Kevlar 시험편에서는 탄자가 섬유를 pull-out하면서 관통하는 현상이 발생하였으나 LBA시험편에서는 섬유의 pull-out 대신 원주방향으로 섬유가 변형되면서 방탄재료가 변형되는 거동을 보여 서로 다른 변형거동을 각각 나타내는 것으로 관찰되었다.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.117-126
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• 2023

To improve the overall performance and realism of your game, it is important to calculate the trajectory of a projectile accurately and quickly. One way to increase realism is to use a ballistic model that takes into account factors such as air resistance, density, and wind when calculating a projectile's trajectory. However, the more these factors are taken into account, the more computationally time-consuming and expensive it becomes, creating a trade-off between overall performance and efficiency. Therefore, we present an optimal solution to find a balance between ballistic model accuracy and computation time. We perform ballistic calculations using numerical methods such as Euler, Velocity Verlet, RK2, RK4, and Akima interpolation, and measure and compare the computation time, memory usage (RSS, Resident Set Size), and accuracy of each method. We show developers how to implement more accurate and efficient ballistic models and help them choose the right computational method for their numerical applications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.507-512
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• 2000

The ob.jective of this study is to determine fracture behaviors(penetrati0n modes) and resistance to penetration duringballistic impact of Al 5052-H34 alloy laminates and anodized Al 5052-H34 alloy laminates. Resistance to penetration is determined by $V_{50}$ ballistic limit, a statical velocity with 50% probability for complete penetration, test method. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed that result from V50 test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with 0" obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ tests with 0" obliquity at room temperature were conducted with projectiles that were able to achieve near or complete penetration during PTP tests. Surface Hardness, resistance to penetration, and penetration modes of A1 5052-H34 alloy laminates compared to those of anodized Al 5052-H34 alloy laminates.y laminates.

• Steel and Composite Structures
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• 제16권3호
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• pp.269-288
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• 2014

Experiments were carried out to investigate the ballistic performance of fiber reinforced plastic(FRP)-steel plates completely penetrated by hemispherical-nosed projectiles at sub-ordnance velocities greater than their ballistic limits. The FRP-steel plate consists of a front FRP laminate and a steel backing plate. Failure mechanisms and impact energy absorptions of FRP-steel plates were analyzed and compared with FRP laminates and single steel plates. The effects of relative thickness, manufacturing method and fabric type of front composite armors as well as the joining style between front composite armors and steel backing plates on the total perforation resistance of FRP-steel plates were explored. It is found that in the case of FRP-steel plates completely penetrated by hemispherical-nosed projectiles at low velocities, the failure modes of front composite armors are slightly changed while for steel backing plates, the dominate failure modes are greatly changed due to the influence of front composite armors. The relative thickness and fabric type of front composite armors as well as the joining style of FRP-steel plates have large effects whereas the manufacturing method of front composite armors has slight effect on the total perforation resistance of FRP-steel plates.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.273-278
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• 2003

Recently, high-performance hybrid composite materials have been used for various industrial fields because of their superior high strength, high stiffness and lower weight. In this study, manufactured hybrid composite materials are composed of two parts. One is hard-anodized Al5083-O alloy as a face material and the other is high strength aramid fiber ($Twaron^{(R)}$ CT709) laminates as a back-up material. Resistance to penetration is determined by protection ballistic limit($V_{50}$, a static velocity with 50% probability for complete penetration) test method. $V_{50}$ 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.

• 한국CDE학회논문집
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• 제20권4호
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• pp.367-374
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• 2015

Sandwich panels consisting of various materials have widely been applied for mitigating dynamic impacts such as ballistic and blast impacts. Especially, the selection of materials for different core set-ups can directly influence its performance. In this study, we design the sandwich panels for alleviating ballistic and blast impacts by controlling the stacking sequence of core materials and their thicknesses. FEM studies are performed to simulate the dynamic behavior of sandwich panels subjected to ballistic and blast impacts. Delamination between the core layers is also considered in the FEM studies for feasible design. Based on the FEM data, kriging models are generated for approximating design space and quickly predicting the FEM outputs. Finally, design optimizations are implemented to find the optimum stacking sequence of core materials and thicknesses with given impact situations.

• 한국산학기술학회논문지
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• 제22권1호
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• pp.372-378
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• 2021

방탄조끼는 전투원의 안전과 생명에 직결되는 군수품으로서, 방탄성능에 대한 요구조건의 충족여부가 무엇보다 중요하다. 우리 군에서는 방탄조끼의 요구 성능을 미 법무성 사업연구소(National Institute of Justice, NIJ)에서 발간한 NIJ STD-0101.06에서 규정하는 Level IIIA 수준으로 요구하고 있으며, 매 로트마다 수락시험을 진행하고 있다. 방탄성능을 평가하는 요소로 사격 시 관통여부 뿐만 아니라, 미 관통 시에도 후면 지지재료의 후면변형 기준인 44 mm 이하에 대한 충족여부도 고려하여 요구 성능에 대한 일치/불일치를 평가하고 있다. 후면변형은 지지재료의 물리적 성질과 탄속에 따른 충격량의 변화 등과 같이 다양한 시험요인이 시험 결과에 영향을 미치게 되는데, 본 연구에서는 이러한 외부인자의 영향성을 제거하기 위한 데이터 처리 시 분산분석을 도입하여 동일한 조건을 갖는 데이터를 추출 하였고, 이를 통해 방탄성능에 대한 분석을 수행하였다. 분석결과, 후면변형과 탄속, 환경처리 유/무 그리고 방호면적과의 상관관계를 확인하였을 뿐만 아니라, 로트별 후면변형 구간 추정을 통해서 양산 공정분석을 수행하였다. 이를 통해서 방탄성능평가에 대한 새로운 방법론을 제시하고, 향후 품질보증 관련 활동에 적용하기 위한 새로운 패러다임을 제시하고자 하였다.

• 한국전산구조공학회논문집
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• 제36권5호
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• pp.331-338
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• 2023

현대의 방탄 장갑은 우수한 관통 저항성을 갖추어야할 뿐만 아니라 군인과 군용차량의 기동성이 확보되어야 하기 때문에 경량화가 중요한 개발 요소가 되었다. 이종 적층 평판 구조의 방탄 장갑의 방탄 성능은 동일 중량 대비 구성 재료의 배열에 따라 달라진다. 본 논문에서는 케블라, 초고분자량 폴리에틸렌 그리고 에바 폼으로 구성된 방탄 장갑의 적층 배열에 따른 방탄 성능을 분석한다. 구성 재료의 두께가 5mm와 6.5mm인 두 가지 경우에서 6가지 적층 배열에 대하여 7.62 × 51mm NATO 탄환의 M80 탄을 856m/s의 속도로 충돌시키는 피탄 해석을 수행하였다. 방탄 성능을 평가하기 위해 이종 적층 평판을 관통한 발사체의 잔류 속도와 잔류 에너지를 측정하였다. 시뮬레이션 결과를 통해 케블라, 초고분자량 폴리에틸렌, 에바 폼의 배열 순서를 갖는 적층 구조가 동일 중량에 대해 가장 우수한 방탄 성능을 가짐을 확인하였다.