• 한국가시화정보학회지
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• 제9권2호
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• pp.27-33
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• 2011

Supersonic liquid jet discharged from a nozzle has been investigated by using a ballistic range which is composed of high-pressure tube, pump tube, launch tube and liquid storage nozzle. High-speed Schlieren optical method was used to visualize the supersonic liquid jet flow field containing shock wave system, and spray droplet diameter was measured by the laser diffraction method. Experiment was performed with various types of nozzle to investigate the major characteristics of the supersonic liquid jet operating at the range of total pressure of 0.8 from 2.14 GPa. The results obtained shows that shock wave considerably affects the detailed atomization process of the liquid jet and as the nozzle diameter decreases, the shock wave angle and the averaged SMD of spray droplet tends to decrease.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.735-738
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• 2011

본 논문에서는 LS-DYNA를 이용하여 원자력 운반용기의 탄자충격에 대한 해석을 수행하였다. 문명의 발달과 더불어 원자력 발전소는 많이 생겼으며 미래에도 유망하다. 원자력 발전소에서 발생되는 사용 후 핵연료에는 환경이나 사람들에게 유해한 방사성 물질이 포함되어 있기 때문에 이를 운반하는 운반용기에 대한 구조적 안전성 확보가 필요하다. 운반용기의 이동과정에서 여러 가지 사고가 날 수 있으므로 이에 대한 대비가 필요하다. 해석에는 운반플라스크와 컨테이너가 사용되었다. 운반플라스크 안에 컨테이너가 들어가 있는 형상을 갖는데 이 부분에 탄자 충격을 가하고, 이 때 운반용기에서 받는 충격량과 변화에 대해 관찰하였다. 탄자도 실제 상황과 비슷하게 하기 위해 보편적으로 사용되는 k-2 소총에 들어가는 것으로 사용하였다. 이를 통하여 운반용기에 탄자충격이 가해졌을 때 구조적 안전성을 평가하였다.

• 제어로봇시스템학회논문지
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• 제1권1호
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• pp.38-42
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• 1995

This paper presents a target scoring method using shock wave signals, which are generated from the supersonic speed of a projectile. The shock wave is detected from three acoustic sensors located in the target plane and the difference of the delay times are measured. The target coordinates are calculated from the effective propagation of velocity (EPV) and the delay times of the shock wave; and the EPV is from the projectile velocity and the delay time. With a comparison between the measurement result and the known coordinates, the accuracy and the usefulness of the proposed scheme is validated.

• 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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.65-66
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• 2015

In this study, it evaluate mecahnical performance and impact resistance performance of fiber reinforced concrete, fiber reinforced mortar and preplace grout mortar. steel fiber, nylon fiber and polypropylene fiber are reinforced 1vol.% 2vol.% 10vol.% by each fiber type. It evaluate impact resistance performance to use projectile 10mm of 400m/s velocity. As a result, mechnical performance and impact resistance performance of fiber reinforced preplace grout mortar are improved a lot by 10% fiber reinforced ratio.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.186-187
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• 2014

Flexural stress and fracture energy of fiber reinforced cementitious composites is increased by bridge effect of reinforced fiber, scabbing failure is restrained. Shape, properties of fiber were SF(steel fiber), PA(polyamide), NY(nylon) have effects on flexural stress and fracture energy, impact resistance improve of fiber reinforced cementitious composites. In this study, local failure properties by impact of high velocity projectile was analyzed by mixing 3 types of fiber which have different shape and properties respectively.

• 한국군사과학기술학회지
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• 제13권3호
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• pp.349-357
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• 2010

In this paper, a numerical code for the interior ballistics has been investigated. The Eulerian-Lagrangian approach and the SMART scheme have been used in the numerical code for the grain combustion. The translational kinetic energy of the projectile and work done against barrel friction have been considered only. The ghost cell extrapolation method has been used for the chamber change with the projectile movement. The calculation results of the numerical code have been compared and verified through those of IBHVG2 code.

• 한국기계가공학회지
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• 제17권5호
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• pp.131-136
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• 2018

Research on space development and satellites is being actively pursued. An interesting field is the study of reliable low-cost space launch vehicles. Since chemical fuel-based launching systems are expensive and take a lot of time and cost to maintain, the EML system, which is an electromagnetic force launching apparatus, is attracting attention. The EML system converts electrical energy stored in a capacitor into magnetic energy, and converts magnetic energy into mechanical kinetic energy, thereby accelerating the projectile. Although studies are actively conducted in the field, it is difficult to solve the equation because the impedance and speedance change with time and the nonlinearity is strong. Many researchers have solved this equation in a variety of methods. In this paper, the velocity analysis of the projectile was carried out by FEM (finite element method) using the commercial electromagnetic analysis program MAXWELL.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.479-490
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• 2020

The hydrodynamic characteristic of transonic motion projectiles with different head diameters are investigated by numerical simulation. Compressibility effect in liquid-phase water are modeled using the Tait state equation. The result shows that with increasing of velocity the compression waves transfer to shock waves, which cause the significant increasing of pressure and decreasing the dimensions of supercavities. While the increasing of head diameter, the thickness, the vapor volume fraction and the drag coefficient of supercavities are all enhanced, which is conducive to the stability of transonic-speed projectiles. The cavity dynamics of the different head projectiles are compared, and the results shows when Mach number is in high region, the truncated cone head projectile is enveloped by a cavity which results in less drag and better stability.

• Structural Engineering and Mechanics
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• 제82권5호
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• pp.587-594
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• 2022

Behavior of concrete elements under the effect of high-speed projectiles has gain increasing interest recently. It's necessary to understand how far the concrete can absorb the effect of bullets in order to save the occupants when design security and military infrastructures. This study presents a total of 18 concrete slabs casted and tested under reinforcement ratios, 0%, 0.35% and 0.7%. Parameters interested were slab thickness, (50 mm, 100 mm, and 150 mm) and type of weapon. All specimens tested to investigate their response under the effect of attacking by two common types of weapon. In general, it was found that projectile penetration was controlled by their thickness regardless the steel reinforcement ratio. However, the steel reinforcement controls the damage.