• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.944-945
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• 2006

A new tungsten heavy alloy with hybrid structure was manufactured for the kinetic energy penetrator. The tungsten heavy alloy is composed of two parts: core region is molybdenum added heavy alloy to promote the self-sharpening; outer part encompassing the core is conventional heavy alloy to sustain severe load in a muzzle during firing. From ballistic test, it was found that the penetration performance of the hybrid structure tungsten heavy alloy is higher than that of conventional heavy alloy. This heavy alloy is thought to be very useful for the penetrator in the near future.

• 대한기계학회논문집
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• 제18권3호
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• pp.573-583
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• 1994

In this study, the shock characteristics for high velocity impact phenomena during the initial shock state by the long rod penetrator are calculated. From these results we re-analyze the one-dimensional hydrodynamic penetration theory by introducing the effective area ratio calculated from the mushroomed strain which is dependent on impact velocity. Calculated penetration depth and mushroomed strain show good agreement with high velocity impact experimental data. In addition we visualize the shock wave propagation in a transparent acryle block.

• 한국시뮬레이션학회논문지
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• 제27권3호
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• pp.109-116
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• 2018

견고표적을 무력화하기 위해서는 높은 침투/관통성능을 가진 침투탄의 개발이 필수적이다. 침투탄의 설계를 위해, 본 논문에서는 노즈 형상 인자들이 침투자의 콘크리트 침투/관통성능에 미치는 영향을 분석하였다. 전산해석은 상용 전산해석 프로그램인 AUTODYN-2D를 사용하여 수행하였다. Forrestal의 시험결과를 사용하여 전산해석의 신뢰성을 검증하였으며, 침투자의 노즈 형상보다는 노즈 길이가 침투/관통성능에 더 큰 영향을 미치는 것을 확인하였다. 또한, 침투자의 노즈 길이가 일정할 경우, 노즈 팁 직경을 특정값까지 증가시켜 침투/관통성능을 향상시킬 수 있음을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제25권3호
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• pp.97-105
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• 2016

본 논문에서는 철근 모사 방법에 따른 관통자의 콘크리트 관통성능 변화를 수치적으로 분석하였다. 관통해석은 상용 전산해석 프로그램인 AUTODYN-3D을 사용하여 수행하였고, Hanchak의 시험 데이터를 사용하여 해석 방법의 신뢰성을 입증하였으며, 철근의 강도와 지름 및 관통자의 충돌위치, 속도를 변수로 사용하여 충돌 해석을 수행하였다. 철근 모사가 관통성능에 미치는 영향을 정량적으로 분석하기 위해, 관통자의 잔류 속도를 계산하여 침투/관통성능을 평가하였다.

• Human Ecology Research
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• 제56권6호
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• pp.619-626
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• 2018

This study investigated the impact of the amount of time online on cyberbullying perpetration of middle school students as well as examined if the justice sensitivity (victim sensitivity and penetrator sensitivity) moderated the relationship between the amount of time online and cyberbullying perpetration. The participants in this study were 236 students (120 boys and 116 girls) from two middle schools located in Seoul and Incheon. The levels of cyberbullying perpetration and justice sensitivity were measured by scales developed by Campfield (2008) and Schmitt et al. (2010), respectively. The participants were also asked to report on how much time they spent online a day. The data were analyzed via descriptive statistics, hierarchical regression, and procedures mentioned by Baron and Kenny (1986). The results revealed that the more the students used the Internet, the more likely they were to become a cyberbullying perpetrator. However, such a tendency was observed only for the students who had a higher level of victim sensitivity, and not for those with a lower level of victim sensitivity. This suggested that victim sensitivity moderated the effect of the amount of time spent on the Internet on cyberbullying perpetration; but, penetrator sensitivity had no moderating effect.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.248-253
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• 2000

This paper presents parametric study of long-rod penetration. Influences of yield stress of penetrator and target material on the penetration results such as crater size and penetrator residual length are contemplated. Numerical experiments are carried out with varying the value of static yield stress of materials. Lagrangian explicit code NET2D was used to perform parametric study. Element eroding algorithm was used to properly simulate long-rod penetration. Analytic and empirical model of long-rod penetration and Taylor test are used to explain the relationships of parameter and simulation results.

• 한국군사과학기술학회지
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• 제8권4호
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• pp.5-13
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• 2005

The impact of a long-rod penetrator into oblique plates with combined obliquity and yaw is investigated. The study was done using a newly developed three dimensional dynamic and impact analysis code, which uses the explicit finite element method. Through the comparison of simulation result with experimental result and other code's result, the adaptability and accuracy of the developed code is evaluated under the complex situation in which yaw angle and oblique angle exist simultaneously. As a result of comparison, it has found that deformed shape, residual length and velocity, rotational velocity of long-rod show good agreement with experimental data. Through this study, the applicability and accuracy of the code as a metallic armour system design tool is verified.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.127-134
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• 2006

The protection capability against an enhanced long rod(L/D=30) with yaw is investigated numerically and compared with that of shorter one(L/D=15). In addition details of interactions between yawed long rods and oblique plate velocity are examined. Through the simulation results, we find that dual flying plates system is more effective with longer rod due to the elongated disturbance. The protection performance is more effective for the penetrator with $+6^{\circ}$ of yaw angle than that with a yaw angle of $-6^{\circ}$.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.712-719
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• 2012

Penetrator with enhanced lateral effect(PELE) is a newconcept projectile, without dynamite and fuze. It consists of high-density jacket, closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE, by AUTODYN-3D code, the calculation models of projectile body and bullet target are established and the process of penetrating aluminum-2024 alloy target of PELE is simulated, and the scattering characteristics after penetrating aluminum-2024 alloy target of PELE are studied by different initial velocity. The explicit finite element analysis of PELE fragmentation was implemented with stochastic failure criterion in AUTODYN-3D code. As expansion of filling, the fragments were obtained velocities and dispersed laterally and further more enhancing the damage area largely. The number and shape of the PELE fragments were different depend on impact velocity and incidence angle of filling which fragment generated during penetration and lateral dispersion process.

• Structural Engineering and Mechanics
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• 제13권2호
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• pp.171-186
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• 2002

Static and dynamic penetration tests of reinforced concrete (RC) slab specimens are described and discussed. The experimental study was aimed at a better understanding of mechanisms that are involved in dynamic penetration, through their identification in static tests, and by establishing their relative influence in similar dynamic cases. The RC specimens were $80{\times}80-cm$ square plates, and they were made of 30 MPa concrete. The non-deforming steel penetrator was a 50-mm diameter steel rod with a conical nose of 1.5 aspect ratio. Impact penetration tests were carried out with an air gun, which launched the projectiles at velocities of up to 300 m/sec. The static tests were conducted using a closed loop displacement control actuator, where the penetrator was pushed at a constant rate of displacement into the specimen. The static tests reveal important mechanisms that govern the penetration process and therefore contribute to a better understanding of RC barriers resistance to non-deforming projectiles impact.