• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.374-375
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.909-910
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• 2010

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.633-636
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• 2006

Impact damage modeling of concrete under high strain rate loading conditions is investigated. A phenomenological penetration model that can account for complicated impact and penetration process such as the rate and loading history response of concrete, the microstructure-penetration interaction etc. is discussed. Constitutive law compatible with Second Law of thermodynamics and coupled damage and plasticity modelling based on continuum damage mechanics are also examined. The purpose of this paper is preliminarily to study with respect to impact and penetration models for concrete before the development of that model.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.231-234
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• 2006

See Full Text

• Defense and Technology
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• no.8 s.270
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• pp.46-55
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• 2001

초기의 화포는 운동에너지만으로 목표물을 파괴하는 탄자를 발사하였으나, 곧 사람들은 에너지를 발산하는 화약을 그 탄자 내에 충전시키고 목표물에 충격시 폭발하도록 해서, 그 목표물을 효과적으로 파괴하는 포탄을 발명하였다. 이러한 개념은 큰 변화 없이 현재까지 지속되어서 현대 전장에서 운용하는 화포, 로켓, 미사일용 탄두와 탄약에 적용되고 있다. 또한 사람이나 경장비, 전차 등을 살상하고 파괴하기 위해 소화기탄이나 전차포용 날개안정 철갑탄처럼 운동에너지만으로 목표물을 파괴하는 탄자가 계속 사용되고 있기도 한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.11a
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• pp.21-21
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• 2000

Thrust Cut-Off 시스템은 로켓 발사체의 분리시의 충격에 의한 비행방향오차 및 비행거리를 감소하고 Pay-Load 부에 추진력을 증가시키고 분리된 추진 기관부의 낙하위치 예측을 용이하게 한다. 이와 같이 중요한 역할을 하게되는 Thrust Cut-Off 시스템에서 스냅링은 핵심적인 역할을 하게 된다. 정상적인 추진체의 작동 시에는 고압의 연소가스를 지탱하고 분리 시에는 쉽게 분리되어 연소가스를 역 분사 시켜야한다.(중략)

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.55-62
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• 2015

An importance of infrastructures' protection against crash or blast loading has been an emerging issue as structures are becoming much bigger and population densities in downtown are growing up. However, there exists no such a standard to evaluate the protection performance of construction material itself. Prior to building standards for protection assessment techniques, this study performed gas-gun propelled projectile impact tests with series of contact-type monitoring systems to investigate the applicability of each sensing type. Through the impact tests, failure modes and protection performances of both normal concrete and UHPC (Ultra High Performance Concrete) reinforced by steel fibers were also evaluated. The results showed that LVDT could be applicable for the impact test among contact-type sensors and UHPC with fibers had a remarkable potential to improve protection against impact loading.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.929-935
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• 2013

This paper presents the results of sizing optimization of ahat-shaped stiffener on a rectangular stiffened panel. The stiffened panel is subjected to impact loading by a projectile with a velocity of 1500-2500 m/s. To determine the size of the hat-shaped stiffener, sizing optimization was performed. The sizing optimization consists of three functions: objective, constraint, and design functions. The objective function is used to maximize the fundamental frequency of the stiffened panel. The constraint function is that the stiffener volume is less than 10% of the plate volume. The design function is the dimensions of the hat-shaped stiffener. By using the stiffened panel with the optimized hat-shaped stiffener, a hypervelocity impact was simulated, and the velocity and kinetic energy on the optimized stiffener was obtained. To evaluate the impact reduction on the stiffened panel, the velocity and kinetic energy of the projectile was normalized and compared.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.6
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• pp.806-814
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• 2019

One of the future weapon systems is the individual smart weapon which has a structure mounted on the forearm of soldiers. The structure may cause injuries or affect the accuracy of fire due to its impact on joints when shooting. This paper proposes human-impact interaction modeling and a verification methodology in order to estimate the impact of fire applied to the forearm. For this purpose, a human musculoskeletal model was constructed and the joints' behavior in various shooting positions was simulated. In order to verify the simulation results, an impact testing device substituting the smart weapon was made and the experiment was performed on a real human body. This paper compares the simulation results performed under various impact conditions and the experimental values in terms of accuracy and introduces methods to complement them. The results of the study are expected to be a basis for a reliable human-impact interaction modeling, and smart individual weapon development.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.409-414
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• 2011

A projectile that passes through a shock wave experiences drastic changes in the aerodynamic forces. These sudden changes in the forces are attributed to the wave structures produced by the projectile-shock wave interaction. A computational study using moving grid method is performed to analyze the effect of the projectile-shock wave interaction. Cylindrical and conical projectiles have been employed to study such interactions. This sort of unsteady interaction normally takes place in overtaking blast flow fields. It is found that the overall effect of overtaking a blast wave on the unsteady aerodynamic characteristics is hardly affected by the projectile configurations. However, it is noticed that the projectile configurations do affect the unsteady flow structures and hence the drag coefficient for the conical projectile shows considerable variation from that of the cylindrical projectile. The projectile aerodynamic characteristics, when it interacts with the secondary shock wave, are analyzed. It is also observed that the change in the characteristics of the secondary shock wave during the interaction is different for different projectile configurations.