• 한국군사과학기술학회지
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• 제18권1호
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• pp.15-21
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• 2015

Rifling Force can be described with projectile velocity, gas pressure and rifling angle, etc. Under the same conditions, the character of the rifling angle decisively influences the rifling force. To reduce the harmful effect, locally distinct maximum of rifling force has to be avoided. The optimal design methodology of rifling angle curve had been developed by combined Fourier series and polynomial function. When it was tried newly to design the rifling angle curve, this design trial caused not to produce the lower rifling force than the existing design. Normally, the curve of the rifling angle is designed first, then the rifling force is set according to the rifling angle curve. However during the cause analysis, new design methodology was established to design the ideal rifling force curve before the rifling angle design. With this new methodology, the above optimal design method was analyzed and its limitation was confirmed.

• 한국군사과학기술학회지
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• 제19권5호
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• pp.629-637
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• 2016

This paper presents a ballistic limit velocity measurement using the support vector machine that classifies two classes, the partial penetration and the complete penetration, by generating a linear separating hyperplane that equally divides the classes. For the ballistic limit velocity measurement, the previous methods(MIL-STD-662F and NIJ-STD-0101.06) have required a large number of experiments that caused high cost and time. However, the proposed method is not only flexible, requiring 0.85 ~ 4.8 times fewer experiments but also reliable, providing less than 2 % difference in results compared to the previous methods. For its validation, live fire experiments were conducted using various thickness SS400 iron plates as a target and two different types of live bullets such as 5.56 mm M193 and 7.62 mm M80.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제4권11호
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• pp.361-368
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• 2015

대공화기사격통제장치에서 유효사거리는 정지한 표적에 대해 충분한 파괴력을 가질 수 있도록 탄속이 음속 이상을 유지하는 거리로 정의되고 있다. 접근하는 표적은 탄과 표적 간 상대속도가 증가하므로 실질적인 교전 사거리는 위의 유효사거리보다 더욱 연장된다. 그러나 기존에 제시된 TOF 계산식은 유효사거리 내에서만 정확하고 유효사거리를 벗어나면 정확하지 못하다. 본 논문은 교전사거리를 보장할 수 있도록 유효사거리 내에서와 유효사거리 밖에서도 충분한 정확도를 가진 실시간 처리가 가능한 탄자비행시간 계산 기법을 제시한다. 시뮬레이션을 통해 30미리 대공 탄에 대한 본 논문의 유용성을 보인다.

• 화약ㆍ발파
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• 제33권4호
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• pp.7-13
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• 2015

최근에 지하공간의 개발과 활용 기술에 대한 수요가 전 세계적으로 급증함에 따라 역학적 안정성과 활용 효율의 측면에서 발파굴착 시 발생하는 손상대 평가는 주요 관심사가 되고 있다. 본 연구에서는 지하공동주변 발파손상대(blast-damaged zone; BDZ)에 대한 폭원모델링을 검증하기 위하여 모멘텀 트랩(momentum trap; MT) 개념을 이용한 일련의 소규모 시험발파를 실시하고, 시험 결과에 따라 LS-DYNA 수치모델의 입력변수들을 수정하였다. 연구 결과, 본 연구에서 제안한 MT 개념을 이용한 모형발파 실험 및 수치모델링 기법은 주어진 조건 하에서 MT의 비산속도를 잘 모사하는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.113-120
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• 2005

In order to investigate the characteristics of penatration and the effect of surface treatment in A15052-H34, Al5082-Hl31 and titanium alloy laminates which were treated by anodizing and PVD(Physical Vapor Desposition) method, ballistic tests were conducted. Thickness of surface membrane in A15052-H34, Al5082-Hl31, were $25{\mu}m$ and that of titanium $0.9{\mu}m$ respectively. Surface hardness test was conducted using micro Vicker's hardness tester. Resistance to penetration is determined by the protection ballistic limit(V50), a statistical velocity with $50\%$ probability for complete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are observed from the results of V50 test and Projectile Through Plate(PTP) test at velocities greater than protection ballistic limit, respectively. Present experimental results derived from this research help to optimize laminate impact behavior by varing the laminate thickness and surface treated materials.

• 한국군사과학기술학회지
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• 제19권3호
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• pp.330-338
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• 2016

Impregnation of shear-thickening fluid(STF) into high-strength fabrics makes a considerable improvement on the ballistic performance of fabric armors. Understanding dissipation augmentation due to shear thickening effects on yarn-yarn and yarn-projectile friction is of great importance in liquid armor research. This paper takes a shearthickening effect into account in numerical simulations by using a velocity-dependent friction model. Impact simulations were performed to validate the friction model as well as to evaluate the ballistic performance of STF-fabrics. Impact simulations on neat fabrics were also conducted to provide baseline results for comparison.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.933-940
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• 2010

A numerical analysis for the space frame structure under ballistic and blast loads was performed using LS-DYNA, a commercial code. The space frame structure was developed to be adapted to the ground vehicle in the future and it was designed to build with Al7039 frames and lightweight multi-layered panels for the purpose of weight reduction and shock mitigation. The analyses have done for side impacts by a cylindrical projectile and Comp. C-4 explosive representing major threats to the vehicle. The deformed shape of the panel section and stresses as well as accelerations of the frames calculated from LS-DYNA were compared to the test results to validate the analysis model. The internal energies for panels and frames from LS-DYNA were also compared to each other to discern their role in absorbing the ballistic and blast impact.

• 한국응급구조학회지
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• 제9권1호
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• pp.95-99
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• 2005

Penetrating neck trauma by gunshot injury involving tracheobronchial tree is rare in Korea. Extensive tissue damage by cavitation, tissue fragmentation and shock wave transmission of high-velocity projectile along with associated organ injury renders high rate of mortality and morbidity. A 28 year old man in military service with gunshot wound in left cervical area presented initial symptoms of severe dyspnea and subcutaneous emphysema. Computed tomography of chest and cervical region as well as bronchoscopic evaluation was performed to confirm highly suspected injury to cervical trachea. Surgical exposure was established through a low collar incision; the damaged segment of 3.5 cm length including 2-4th tracheal rings was resected out and end-to-end anastomosis was performed. Bleeding from lacerated anterior jugular vein was controlled by ligation of both ends and a K2 bulllet was found upon inner border of body of first rib, medial to right carotid sheath and removed out. Cervical esophagus, carotid artery, internal jugular vein and recurrent laryngeal nerve were spared. Extubation was done on the first postoperative day and postoperative course until discharge on nineth postoperative day remained uneventful.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.659-665
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• 2008

The 1-D numerical study of the interior ballistics has been conducted. The unsteady compressible 1-D CFD code using SIMPLER algorithm and QUICK scheme has been developed. The mathematical model of the two-phase flow has been established for the behavior of the interior ballistics. The moving boundary due to the projectile motion as the physical phenomena of the interior ballistics results in the varied control volume. In order to analyze the moving boundary, the numerical codes, which apply the ghost-cell extrapolation method and the Lagrangian method respectively, have been developed. The ghost-cell extrapolation method has been used in the Eulerian coordinate system. The Lagrangian method has been used in Non-Eulerian coordinate system. These codes have been verified through the analysis of the free piston motion problem in the tube. Through this study, the basic techniques of the numerical code for the multi-dimensional two-phase flow of the interior ballistics have been obtained.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.723-728
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• 2008

We performed numerical analysis of base drag phenomenon, when a projectile with backward step flies into atmosphere at supersonic speed. We compared with other researchers. From our previous studies that were 2-dimensional simulation, we found out from sophisticated simulations that need dense mesh points to compare base pressure and velocity profile after from base with experimental data. Therefore, we focus on high order spatial disceretization over 3rd order with TVD such as MUSCL TVD 3rd, 5th, and WENO 5th order, and Limiters such as minmod, Triad. Moreover, we enforce to flux averaging schemes such as Roe, RoeM, HLLE, AUSMDV. In present, one dimensional result of Euler tests, there are Sod, Lax, Shu-Osher and interacting blast wave problems. AUSMDV as a flux averaging scheme with MUSCL TVD 5th order as spatial resolution is good agreement with exact solutions than other combinations. We are carrying out the same approaches into 3-dimensional base flow only candidate flux schemes that are Roe, AUSMDV. Additionally, turbulence models are used in 3-dimensional flow, one is Menter s SST DES model and another is Sparlat-Allmaras DES/DDES model in Navier-Stokes equations.