• 한국군사과학기술학회지
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• 제18권5호
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• pp.566-573
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• 2015

The most important factor for the penetration performance of shaped charge is the liner design. By designing the liner to have properties of both high jet tip velocity and long jet break-up time, the better penetration performance could be acquired. Usually it is very difficult to satisfy above two conditions simultaneously. In this study, the liner with the shape of ogive was developed to have relatively larger jet mass compared to the conventional trumpet liner. The designed shaped charge showed jet properties with high jet tip velocity and long jet break-up time by using ogive liner and wave shaper. A commercially available hydro-dynamic code AUTODYN-2D was used for numerical analysis of jet formation. The flash X-ray test and the static penetration test were conducted to verify the results of numerical analysis.

• 한국전산구조공학회논문집
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• 제32권2호
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• pp.133-140
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• 2019

본 논문은 Shaped charge jet(SCJ)의 관통 과정을 유한요소해석을 통해 모사하여 제트 입사속도, 관통률 그리고 관통량 증분과 같은 물리량들을 획득하였다. 이 물리량들을 hydrodynamic 이론에 적용하여 입사 제트 속도의 효율을 분석한 결과, 입사 속도가 빠른 제트의 관통 효율은 이어지는 느린 제트에 비해 높은 것을 확인하였다. 이 효율은 hydrodynamic limit(HL) 미만인 제트인 경우 큰 폭으로 감소하였다. 한편, 시간에 따른 관통량 증분과 제트 소모량의 비교는 SCJ의 이론적인 관통현상 분석을 위해서는 길이 연장 효과를 고려해야함을 보였다.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.378-387
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• 2009

The shaped charge consists of the cast or pressed explosive and the metal liner. The pressure formed in detonation wave is so high that the liner is collapsed and the jet of high temperature, pressure and velocity is produced. The jet penetrates the target. In this paper, the simulation for optimization of flexible linear shaped charge(FLSC) was carried out by AUTODYNE program. Based on the results of simulation, we made a prototype of FLSC and evaluated penetration performance, flexibility and its application. The test result of prototype was compared with that of simulation.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.574-581
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• 2015

In this paper, the effect of high voltage current pulse against shaped charge jet was analyzed through the visualization of jet behavior using flash X-ray and comparison of depth of penetration(DOP) into RHA(Rolled Homogeneous Armor) witness plates. The behavior of jet particles has been acquired using a flash X-ray equipment when current pulse was applied into the metal jet of a shaped charge(SC) warhead. Typical results such as jet breakup and radial jet dispersion, which are due to electromagnetic pressure by current pulse, have been obtained. Dozens of penetration experiments using a shaped charge with 55 mm diameter were performed according to various combinations of major parametric variables such as electrode spacing, standoff distance from SC warhead to electrode, and charge voltage. Subsequently, interrelations between major parametric variables and DOPs into RHA were analyzed.

• 한국분말재료학회지
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• 제6권1호
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• pp.69-74
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• 1999

The microstructure of the reagion of carters, created by Cu and W-Cu shaped charge jets, in a 1020 mild steel target has been intestiaged. The region ahead of the crater created by the Cu shaped charge jet, reveals dramatic grain refinement implying the occurrence of a dynamic recrystallization, while that of W-Cu one dose a martensitic transformation indicative of heating up to an austenitic region followed by rapid cooling.The impacting pressure calculated when the W-Cu shaped charge jet encounters the target is higher than that of the Cu one. The micro-hardness of the region ahead of the crater created by the W-Cu shaped charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug remained in the inside of the craters depicts the occurrence of the remarkable elongation of W particles during the liner collaphse. From these results, the microstructural variation of the region ahead of the crater with Cu and W-Cu shaped charge jets is discussed in trems of the pressure dependency of the transformation region of ferrite and austenite phases.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.577-584
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• 2014

In this study, the behavior of a shaped charge projectile's metal jet was analyzed using flash radiography. The projectile was installed horizontally to observe the behavior of jet for enough time. While the X-ray tube heads are fixed at one point, the behavior range of the jet is wide in this experimental set up, therefore the angle between the X-ray tube heads and the jet tip is changed continuously as jet moves forward. Jet particle's locations calculated from the X-ray films become different from their real positions under this situation because of the film to object distance(FTOD) and correction for error by FTOD is required. In this study, a method was devised to correct the error by FTOD and this was applied for the investigation of jet behavior of a 70 mm caliber's shaped charge.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2001년도 추계학술강연 및 발표대회
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• pp.46-46
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• 2001

The microstructure of the 1020 mild steel target in the region ahead of craters, made by colliding against Cu and W-Cu shaped-charge jets. has been investigated in the present work. The region ahead of the crater impacted by the Cu shaped-charge jet reveals grain refinement implying the formation of sub-grains, while that of W-Cu one leads to martensitic transformation indicating that the region was heated up to an austenitic region which was followed by rapid cooling. The pressure of W-Cu shaped-charge jet impacting against the target when calculated is higher than that of Cu one. The microhardness of the region ahead of the crater impacted by the W-Cu shaped-charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug that remains inside of the crater depicts the occurrence of the remarkable elongation of W particles during the liner collapse. The microstructural evolution of the region ahead of the crater is discussed on the basis of the pressure dependency of the ferrite/austenite transformation in the steel.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.270-277
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• 1999

The ballistic capability of an alumina-rich oxide armor ceramic against a shaped jet was characterized as a function of penetration depth in a layered target structure. The penetration resistance of the ceramic, based upon the determination of penetration velocity, was not equally realized throughout the depth of penetration. It was abnormally low at an early stage of penetration, followed by a sudden increase to reach ~16GPa thereafter. There was no apparent change in such a profile with respect to the lateral size of the specimen. Based upon 2-D flash x-ray radiography and 3-D Hull code simulation, the feasibility of forming a pressure-induced predamnaged zone in front of the jet tip was speculated to foster an increased penetration velocity in the initial stage penetration, resulting in the diminished penetration resistance. The disappearance of such a predamaged zone with penetration was interpreted to restore the resistance of the ceramic in the later penetration stage.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.550-556
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• 2012

In this study, a series of ballistic experiments have been performed to investigate the protection mechanism of some inert reactive cassettes against shaped charge jet. Three kinds of material were tested as a core material of the inert cassettes, i.e. one of rubber materials, a high modulus and high strength composite material used for ballistic protection and a mixture of energetic materials. Parameters such as deformation of the cassettes, occurrence time of jet distortion, leading jet length and residual penetration depth were investigated from the experiments and they were compared to each other quantitatively according to the jet incidence angles. The results show that the increment of cassette deformation caused jet distortion to occur early and jet distortion brought decrease of the length of leading jet. Then the decrease of the length of leading jet accompanied the decrease of residual penetration depth.

• 한국전산구조공학회논문집
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• 제32권3호
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• pp.199-203
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• 2019

속도 4km/s 이상인 초고속 제트의 관통 깊이는 제트와 표적의 밀도 비를 통해 기술된다. 반면에 동일한 밀도인 경우 표적들 사이의 강도 차이는 관통 깊이 차이에 영향을 주지 않는다. 본 연구는 초고속 제트의 "강도 무관성"에 관한 연구를 다룬다. 이를 위해 초고속 성형작약탄두 제트(SCJ)에 의해 발생된 크레이터 압력의 변화를 유한요소해석을 통해 계산하고, 철강소재의 polymorphic 상변이 발현 가능성을 조사하였다. 결과적으로 초고속 제트는 표적 크레이터에 polymorphic 상변이를 일으킬 수 있고, 이로 인한 표적의 파괴 인성 저하가 강도 무관성의 원인으로 예측된다.