• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.1-14
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• 1998

Underwater explosion properties for TNT, an ideal explosive, and DXD-04, a nonideal explosive, were numerically modeled with a one-dimensional Lagrangian hydrodynamic code. The equation of state parameters for detonation products for TNT and DXD-04 were obtained from the BKW code, assuming complete reaction. Burn of TNT was modeled by using the Chapman-Jouguet(CJ) volume burn technique, a programmed-burn technique, assuming instantaneous detonation reaction. Burn of DXD-04 was modeled by using the same technique and by using the reaction rate calibrated from two-dimensional steady-state detonation experiments. The calculations for TNT reproduced the experimental peak pressure of the shock wave propagating through water with an error of $3.0\%$ and the experimental oscillation period of the bubble formed of detonation products with an error of $2.3\%$. For DXD-04, the CJ volume burn technique could not reproduce the experimental observations. When the reaction rate calibrated from two-dimensional steady-state detonation experimental data, the calculated peak pressure was slightly higher by $7.3\%$ than the experimental data, but the calculated shock profile was in good agreement. The bubble period was reproduced with an error of $1.8\%$. These results demonstrated that underwater explosion properties for an ideal explosive can be predicted by using a programmed burn technique, and that, however, those for a nonideal explosive can be predicted only when a well-calibrated reaction rate is used.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.102-114
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• 2004

The present work has been developed the interpretation processor including the behavior of material failure and the separation phenomena under transient dynamic loading (the operation of explosive bolt) using AUTODYN V4.3, SoildWork 2003 and TrueGrid V2.1 programs. It has been demonstrated that the interpretation in ridge-cut explosive bolt under dynamic loading condition should be necessary to the appropriate failure model and the basic stress of bolt failure is the principal stress. The use of this interpretation processor developing the present work could be extensively helped to design the shape and the amount of explosives in the explosive bolt having a complex geometry. It is also proved that the interpretation processor approach is an accurate and effective analysis technique to evaluate the separation mechanism in explosive bolts.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.99-108
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• 2006

Aerospace applications use pyrotechnic devices with many different functions. Functional shock, safety, overall system cost issue, and availability of new technologies, however, question the continued use of these mechanisms on aerospace applications. Release device is an important example of a task usually executed by pyrotechnic mechanisms. Many aerospace applications like satellite solar panels deployment or weather balloon separation need a release device. Several incidents, where pyrotechnic mechanisms could be responsible for spacecraft failure, have been encouraging new designs for these devices. The Frangibolt is a non explosive device which comprises a commercially available bolt and a small collar made of shape memory alloy (SMA) that replace conventional explosive bolt systems. This paper presents the modeling and simulation of Frangiblot by the change of bolt size and notch geometry. This analysis may contribute to improve the Frangibolt design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.462-468
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• 2017

KYP model is a pressure-based chemical kinetics that describes shock to detonation transition of energetic materials. In this research, the parameters of KYP model and JWL EOS for PETN-based explosive, namely PBXN-301, were determined. A series of unconfined rate stick tests and two dimensional hydrodynamic simulation were conducted to obtain the size effect behaviour of the explosive. As a result, it was confirmed that the parameters obtained from KYP modeling have more accuracy to predict the detonation velocities according to the inverse radius of PBXN-301 than the qualitatively obtained LLNL constitutive equations.

• Computers and Concrete
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• v.9 no.4
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• pp.311-325
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• 2012

In this paper, we examine the behavior of the High-Rate Brittle Microplane (HRBM) concrete model based on a series of penetration experiments. These experiments were conducted with three different slab thicknesses (127, 216 and 254 mm) that provided a significant challenge for the numerical simulations. The 127 mm slab provided little resistance, the 216 mm slab provided nominal resistance and the 254 mm slab approached the perforation limit thickness of the projectile. These experiments provide a good baseline for evaluating material models since they have been shown to be extremely challenging; in fact, we have not encountered many material models that can provide quantitatively predictive results in terms of both projectile exit velocity and material damage. In a companion paper, we described the HRBM material model and its fit to various quasi-static material property data for WES-5000 concrete. In this paper, we show that, when adequately fit to these quasi-static data, the HRBM model does not have significant predictive capabilities, even though the quasi-static material fit may be exceptional. This was attributed to the rate-dependent response of the material. After various rate effects were introduced into the HRBM model, the quantitative predictive nature of the calculations dramatically increased. Unfortunately, not much rate-dependent material property data are in the literature; hence, accurate incorporation of rate effects into material models is difficult. Nonetheless, it seems that rate effects may be critical in obtaining an accurate response for concrete during projectile perforation events.

• Clean Technology
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• v.20 no.4
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• pp.398-405
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• 2014

In the treatment of spent high energetic materials, the issues such as environmental pollution, safety as well as working capacity should be carefully considered and well examined. In this regard, incineration has been recommended as one of the most promising processes for the disposal of such explosives. Due to the fact that high energetic materials encompass various types and their different characteristics, the technology development dealing with various materials is not an easy task. In this study, rigorous modeling and dynamic simulation was carried out to predict dynamic physico-chemical phenomena for research department explosive (RDX). Plug flow reactor was employed to describe the incinerator with 263 elementary reactions and 43 chemical species. Simulation results showed that safe operations can be achieved mainly by controlling the reactor temperature. At 1,200 K, only thermal decomposition (combustion) occurred, whereas increasing temperature to 1,300 K, caused the reaction rates to increase drastically, which led to ignition. The temperature further increased to 3,000 K which was the maximum temperature recorded for the entire process. Case studies for different operating temperatures were also executed and it was concluded that the modeling approach and simulation results will serve as a basis for the effective design and operation of RDX incinerator.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• The Journal of Society for e-Business Studies
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• v.1 no.1
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• pp.195-207
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• 1996

It is required the electronic commerce system for satisfying the various information needs of user groups on the high speed communication networking. However, its information amounts will be explosive, and make it difficult for users to locate information they are interested in. Therefore we have developed the architecture of information searching platform for electronic commerce which searches and gathers information about electronic commerce site on internet and builds the keywords index database for serving the client's requests in order to provide non-professionals and small companies etc., with access easily to retrieval information.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.349-352
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• 2007

In this paper, we describe the modeling of ablation based laser applications for innovative use in the military In the laser ignition system, a metal confinement is ablated with the high intensity pulsed energy, triggering a thermal ignition of the confined high explosives. The constitutive equations for the laser source, deformation of metals, and explosion of energetic materials are described.

• Explosives and Blasting
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• v.34 no.2
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• pp.31-38
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• 2016

The hydrodynamics code is a numerical tool developed for modeling high velocity impacts where the materials are assumed to behave like fluids. The hydrodynamics code is widely used for solving impact problems, such as rock blasting using explosives. For a realistic simulation of rock blasting, it is necessary to model explosives numerically so that the interaction problem between rock and explosives can be solved in a fully coupled manner. The equation of state of explosives, which describes the state of the material under given physical conditions, should be established. In this paper, we introduced the hydrodynamics code used for explosion process modeling, the equation of state of explosives, and the determination of associated parameters.