• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.465-470
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• 2022

This paper studied the high-velocity impact behavior characteristics of metal materials by crosschecking the high-velocity impact analysis with the high-velocity impact experiment results of aluminul 6061. The coefficients of the Huh-Kang material model and the Johnson-Cook fracture model were calculated through quasi-static using MTS-810 and dynamic experimenting using the Hopkinson bar equipment for high-velocity impact analysis. The penetration velocity and shape were predicted through high-velocity impact analysis using the LS-DYNA. The resultes were compared with the experiment results using a high-velocit experiment equipment. It is intended to be used the containment evaluation research for aircraft gas turbine engine blade.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.107-114
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• 2013

In this study we experimentally evaluated an impact resistant performance of fiber reinforced concrete in the moment of explosion by high-velocity projectile with emulsion explosive. To assess the impact resistance, we conducted the impact test of high-velocity projectile which reaches an impact speed of 350 m/s and the experiment of contact exploding emulsion explosive. As a result, bending and tensile performance depending on type of PVA, PE fiber (polyvinyl alcohol fiber, polyethylene fiber) and steel fiber affects destruction of rear side in the form of spalling. Destroying the backside of the concrete compressive strength compared to suppress the bending and tensile performance is affected. In addition, the experiment shows that the destruction patterns of concrete specimen producted by high velocity impact and contact explosion are significantly similar. Therefore, it is possible to predict the destruction patterns of specimens in the situation of contact explosion by high-velocity projectile.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.663-668
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• 2014

Mechanical and electrical devices in various forms are used in many different fields. These can be exposed to external environmental factors such as shock. Therefore, a shock test machine is commonly used to test these devices and evaluate their shock resistance. In this test, the break-down or permanent deformation and malfunction of inner parts due to a high stress or acceleration can be evaluated. As part of a shock test machine, a velocity generator is needed to create shocks between objects. In this study, a hydraulic velocity generator was conceptually designed and an AMESim model was developed to simulate the velocity under different conditions. Simulation results using this model were compared with the test results from a reduced-size velocity generator, and we designed a velocity generator that fits the target payload and velocity using the simulation results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.791-799
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• 2016

To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding $10^4\;s^{-1}$. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.389-390
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• 2009

Recently, building structure damage and number of lives lost by bomb terror is increasing. Therefore, in this study, present basic data for development of impact resistance performance by evaluation on the impact resistance performance of fiber reinforced concrete by high velocity steel projectile test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.328-336
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• Korean Journal of Materials Research
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• v.7 no.9
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• pp.795-804
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• 1997

전면재를 알루미나, 후면재를 Kevlar또는 S-2 유리 섬유강화 복합재료로 접합한 이종재료 장갑에 대하여 알루미나의 두께 변화와 복합재료의 적층구조에 따른 고속충격 특성 변화에 대하여 연구하였다. 또한 시험재료의 동적 관통현상을 분석하기 위하여 고속촬영기법이 이용되었다. 시험결과, 전면재인 알루미나는 충격탄자 직경의 80% 상당하는 두께(본 실험에서는 6nm)인 경우 양호한 방탄성능을 보였다. 후면재인 복합재료는 섬유를 alternating 주조로 적층한 경우가 laminar구조로 적층한 것에 비하여 더 우수한 방탄성능을 나타내었다.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.75-83
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• 2009

Collision behavior of clash cushion occurs for a second of less than 0.4sec usually so that it is too hard to calculate numerically. Therefore, for development of trash cushion, it rely on full-scale vehicle crash test without any design procedure. Occupant safety indices if calculated from acquired data by data measurement system and collision behavior of vehicle and crash cushion is filming using high-speed camera in the crash test. But practical ufo scope of high-speed camera is limited and it is not using to calculated the occupant safety indices or analyzed the energy dissipated mechanism of crash cushion. This work is to estimate to be suitable or not for compare the data from measurement system with the data from high-speed camera. And also it is to grope for practical use scheme to calculation of occupant safety indices or analysis of collision behavior.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.41-44
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• 2007

Ground test facility for the hypersonic propulsion system was designed, constructed and performance test was conducted. The design point was selected using quasi，1-Dimensional CFD analysis before the conceptual design for construction of hypersonic facility After that, specific designs for performance and components were completed using unit analysis CFD code and performance tests were conducted for the various operation conditions.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.11-17
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• 2009

The drop impact reliability comes to be important for evaluation of the life time of mobile electronic products such as cellular phone. The drop impact reliability of solder joint is generally affected by the kinds of pad and reflow number, therefore, the reliability evaluation is needed. Drop impact test proposed by JEDEC has been used as a standard method, however, which requires high cost and long time. The drop impact reliability can be indirectly evaluated by using high speed shear test of solder joints. Solder joints formed on 3 kinds of surface finishes OSP (Organic Solderability Preservation), ENIG (Electroless Nickel Immersion Gold) and ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) was investigated. The shear strength was analysed with the morphology change of intermetallic compound (IMC) layer according to reflow number. The layer thickness of IMC was increased with the increase of reflow number, which resulted in the decrease of the high speed shear strength and impact energy. The order of the high speed shear strength and impact energy was ENEPIG > ENIG > OSP after the 1st reflow, and ENEPIG > OSP > ENIG after 8th reflow.