• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.567-572
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• 2001

In order to investigate the fracture behaviors(penetration modes) and resistance to penetration during ballistic impact of Titanium alloy laminates and nitrified Titanium alloy laminates which were treated by PVD(Physical Vapor Deposition) method, ballistic tests were conducted. Evaporation, sputtering, and ion plating are three kinds of PVD method. In this research, Ion plating was used to achieve higher surface hardness and surface hardness test were conducted using a Micro vicker's hardness tester. Resistance to penetration is determined by the protection ballistic limit($V_{50}$), a statistical velocity with 50% probability for complete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed at and above ballistic limit velocities, as a result of $V_{50}$ test and Projectile Through Plates (PTP) test methods. PTP tests were conducted with $0^{\circ}$ obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ test with $0^{\circ}$ 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 Titanium alloy laminates are compared to those of nitrified Titanium alloy laminates.

• 한국추진공학회지
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• 제12권3호
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• pp.49-59
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• 2008

본 연구에서는 155 mm 고체연료 램제트 추진 탄의 설계방법을 제시하였고 수학적 모델링을 통한 비행성능 해석 프로그램을 개발하였다. 비행성능 해석을 통하여 추력, 비추력, 압력 회복률, 충격파의 위치, 항력의 크기 등 비행 중 램제트 성능을 예측하였다. 비행탄도 해석결과 RAP에 비하여 90 % 정도의 사거리 증대효과를 나타내었다. 또한 노즐 출구 면적비와 흡입구 면적의 변화에 따른 사거리 변화의 추이를 살펴보았다. 제시된 모델링과 시뮬레이션 방법은 램제트 탄의 개발에 필요한 설계 자료로 매우 유용할 것이다.

• 한국정밀공학회지
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• 제20권12호
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• pp.126-134
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• 2003

In order to investigate the effect of surface treatment in Aluminium alloy and Titanium alloy which are used to armor material during ballistic impact, a ballistic testing was conducted. Anodizing was used to achieve higher surface hardness of Aluminium alloy and Iron plating in PVD(Physical Vapor Deposition) method was used to achieve higher surface hardness of Titanium alloy. Surface hardness test were conducted using a Micro victor's hardness tester. Ballistic resistance of these materials was measured by protection ballistic limit(V-50), a statical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed from the results of 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 projectile. V-50 tests were conducted with 0$^{\circ}$obliquity at room temperature with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration. and penetration modes of surface treated alloy laminates are compared to those of surface non-treated alloy laminates. A high speed photography was used to analyze the dynamic perforation phenomena of the test materials.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.338-338
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• 2011

The behavior of hydroxide ions on water-ice films was studied by using $Cs^+$ reactive ion scattering (RIS), low energy sputtering (LES) and temperature-programmed desorption (TPD). A $Cs^+$ beam of a low kinetic energy (<100 eV) from $Cs^+$ ion gun was scattered at the film surface, and then $Cs^+$ projectiles pick up the neutral molecules on the surface as $Cs^+$-molecule clusters form (RIS process). In LES process, the preexisting ions on the surface are desorbed by the $Cs^+$ beam impact. The water-ice films made of a thick (>50 BL) $H_2$O layer and a thin $D_2O$ overlayer were controlled in temperatures 90~140K. We prepared hydroxide ions by using Na atoms which proceeded hydrolysis reaction either on the ice film surface or at the interface of the $H_2O$ and $D_2O$ layers.[1] The migration of hydroxide ions from the $H_2O/D_2O$ interface to the top of the film was examined as afunction of time. From this experiment, we show that hydroxide ions tend to reside at the water-ice surface. We also investigated the H/D exchange reactions of $H_2O$ and $D_2O$ molecules mediated by hydroxide ions to reveal the mechanism of migration of hydroxide to the ice surface.

• 한국항공우주학회지
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• 제44권6호
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• pp.502-511
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• 2016

최근 다양한 형태와 기능을 갖춘 스마트 무기들이 개발되고 있다. 화포탄의 경우 스마트 탄을 개발하기 위한 초기 연구로 신관 내부에 GNSS 수신기를 장착하여 탄자의 비행위치를 정밀하게 측정하고 이를 바탕으로 탄착점을 추정하는 연구가 진행되고 있다. 하지만, 수신기 성능 및 수신된 데이터에 포함된 다양한 오차유발 원인들로 인해 항법데이터의 위치정확도에 오차가 발생하게 된다. 본 논문에서는 PRODAS로부터 얻은 모의궤적 데이터를 수신기로부터 얻은 항법데이터에 포함된 PDOP 가중치를 적용하여 정합함으로써 탄의 발사부터 탄착까지의 전체 비행궤적 및 탄착점을 보다 정밀하게 추정하는 개선된 알고리즘을 소개한다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.936-938
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• 2017

본 논문에서는 발사체 및 무기체계의 연소관 등에 적용되고 있는 복합재의 볼트체결부에 대한 점진적 파손 해석을 수행하였다. 해석에 사용된 Hashin 파손 판정식은 복합재 파손모드에 따라 섬유 인장 파손 모드(Fiber tensile failure mode), 섬유 압축 파손 모드(Fiber compressive failure mode), 기지 인장 파손 모드(Matrix tensile failure mode), 기지 압축 파손 모드(Matrix compressive failure mode)의 4가지 모드로 고려되었으며, 이를 이용해 user subroutine인 UMAT을 개발하였다. 점진적 파손 해석을 통해 복합재 볼트체결부에 대한 파손강도를 예측 하였으며, 이를 시편 시험 결과와 비교하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권6호
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• pp.762-781
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• 2018

This paper presents the ballistic armor performance examination and thickness estimation for the latest naval ship structure materials in the Republic of Korea. Up to date, research regarding methods of ballistic experiments establishing database on the latest hull structure materials as well as a precise method of estimating required thickness of armor against specific projectiles have been rarely researched. In order to build a database and estimate proper thicknesses of structure materials, this study used four structure materials that have been widely applied in naval ships such as AH36 steel, AL5083, AL5086, and Fiber Reinforced Plastics (FRP). A $7.62{\times}39mm$ mild steel core bullet normally fired by AK-47 gun was considered as a threat due to its representativeness. Tate and Alekseevskii's penetration algorithm was also used to calculate a correction factor (${\alpha}$) and then estimate the armor thickness of naval ship hull structure materials with a given impact velocity. Through live fire experiments, the proposed method performance difference was measured to be 0.6% in AH36, 0.4% in AL5083, 0.0% in AL5086, and 8.0% in FRP compared with the experiment results.

• 한국진공학회지
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• 제5권1호
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• pp.25-32
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• 1996

An ERD-TOF system is constructed for the nondestructive depth profiling of light elements in thin films in the range of several thousand angstroms. The particles, recoiled by 10 $MeV^{35}Cl$ projectiles, were detected by a Time-Of-Flight spectrometer composed of a MCP (Micro Channel Plate) and a SSB (Silicon Surface Barrier) detector. A two parameter data acquisition system composed of two PC's was constructed for registering simultaneous time and energy signals. A $Si_3N_4$/poly-Si/$SiO_2$/Si sample was anlayzed and the result is compared with RBS. The detection limit, maximum probable depth and depth resolution for light elements in silicon are about $4\times10^{14}atoms/\textrm{cm}^2$, 5, 000$\AA$ and 100$\AA$, respectively.

• 한국안전학회지
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• 제29권4호
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• pp.1-8
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• 2014

In this study, the numerical simulation using AUTODYN-3D program was investigated angle trajectory prediction for inclined impacts of projectiles. The penetration and perforation of polycarbonate plate by 7.62 mm projectile was investigated numerically. The characteristic structure of the projectile's trajectory in the polycabonate plates was studied. Two combined failure criteria were used in the target plate, and the target plate was modeled with the properties of polycarbonate for simulating the ricochet phenomenon. The effect of the angle of inclination on the trajectory and kinetic energy of the projectile were studied. The dynamic deformation behaviors tests of polycabonate were compared with numerical simulation results which can be used as predictive purpose. From the simulation, the ricochet phenomenon was occurred for angles of inclination of $0^{\circ}{\leq}{\theta}{\leq}20^{\circ}$. The projectile perforated the plate for ${\theta}{\leq}30^{\circ}$, thus defining a failure envelope for numerical configuration. The numerical analyses are used to study the effect of the projectile impact velocity on the depth of penetration (DOP). It can be observed that the residual velocities were almost linear relative to penetration velocities. It means that polycarbonate has high resistance at higher velocities.

• 한국군사과학기술학회지
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• 제19권1호
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• pp.95-104
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• 2016

To make a firing table of artillery with trajectory simulation, a precise trajectory model which corresponds with real firing test is required. Recent 4-DOF modified point mass trajectory model is considered accurate as a theoretical model, but fitting coefficients are used in calculation to match with real firing test results. In this paper, modified point mass trajectory model is presented and method of setting ballistic coefficient is introduced by applying optimization algorithms. After comparing two different algorithms, Particle Swarm Optimization and Covariance Matrix Adaptation - Evolutionary Strategy, we found that using CMA-ES algorithm gives fine optimization result. This fitting coefficient setting method can be used to make trajectory simulation which is required for development of new projectiles in the future.