• Explosives and Blasting
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• v.35 no.3
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• pp.21-30
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• 2017

When explosives explode in water, the effect of post-explosion gas after explosion should be considered, unlike explosion in the air. During explosion in water, the propagation velocity of the explosion pressure is faster than when the explosion occurs in the air. The generated gas is diffused and trapped in the form of bubbles by water before the energy is dissipated. At this time, the bubble expands and contracts, creating a shock wave. In order to investigate this series of phenomena, a cylinder type steel water tank capable of observing the interior was fabricated and explosion experiments were conducted. In this study, a small amount of shell-free pentolite was exploded in water. Experiments were performed to observe the behavior of the generated gas bubble as well as to measure the shock wave generated. We designed the experimental method of underwater explosion and examined the results.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.454-460
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• 2013

We present qualitative and quantitative component analyses on compound explosives via Terahertz time-domain spectroscopy (THz-TDS) based on a combination of wavelet thresholding and wavelength selection. Despite its importance, the field of signal processing of THz signals of compound plastic explosives is relatively unexplored. In this paper, experiment results from explosives Composition B-3 and Pentolite are newly presented, suggesting a novel signal processing procedure for in situ compound explosives detection. The proposed signal processing method demonstrates effective component analysis even in noisy and humid environments, showing significant decrease in component concentration percentage error of approximately 22.7% for Composition B-3 and 48.8% for Pentolite.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.223-226
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• 2015

A pyrotechnic system that consists of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. We apply a level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the pyrotechnic system are quantitatively investigated.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.75-85
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• 2016

A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. Despite of its common use, numerical study of such pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a Eulerian level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the gap test are quantitatively investigated.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.5
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• pp.439-446
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• 2017

This paper deals with an experimental study of the dynamics of an underwater bubbles and shock waves, generated by rapid underwater release of highly compressed gas. Aribag inflators, which are used for automobile's airbag system, are used to generate the extremely-rapid underwater gas release. Experimental studies of the complex underwater bubble dynamics as well as underwater shock wave were carried out in a specifically designed cylindrical water tank. The water tank is equipped with a high-speed camera and pressure sensors. The high-speed camera was used to capture the expansion and collapse of the gas bubble created by inflators, while pressure sensors was used to measure the underwater shock propagation and magnitudes. The experimental results were compared against the results of explosion of pentolite explosive. Several physical phenomena that has been observed and discussed, which are different from the explosive underwater explosion.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.122-128
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• 2004

Internal blast performance test on developed explosives was carried out. Internal blast means a blast wave in closed chambers like tunnels, bunkers, operation center and chamber of ships. We used Anpa tunnel for our test facility. We performed two series of tests to measure internal blast of developed explosives. Three different kinds of cast PBXs, DXD-09, DXD-10, DXD-18, and conventional explosive, Tritonal, were used in our test. The explosives were cast as a charge of 108mm diameter in a plastic tube of a 3mm thickness. The length of charges 4ere adjusted as a weight 3kg. A melt-cast explosive, tritonal, was used as a reference. Pentolite booster was used. The cylindrical boosters have a 95mm diameter and 47.5mm height. The results showed that there may be some differences between the performances in the air blast tests and those in the internal blast tests. The results showed that DXD-10, the best performance in air blast tests, showed the poorest performance in internal blast among the explosives tested. On the other hand, DXD-18 showed exactly the opposite trend. This is probably due to the highest contents of aluminum and inert binder in DXD-18. DXD-18 has $38\;wt\;\%$ of aluminum and $17\;wt\;\%$ of inert binders.