• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.715-722
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• 2014

In this paper, internal blast effect of reinforced concrete core structure were investigated using Ansys Autodyn, which is a specialized hydrocode for the analysis of explosion and impact. It is expected that internal blast case can give additional damage to the structure because it causes rebound of blast loads. Therefore, in this paper, the hazard of internal blast effect is demonstrated using UFC 3-340-02 criteria. In addition, analysis result of Autodyn, experimental result regarding rebound of blast load, and example of UFC 340-02 are compared to verify that Autodyn can analyze internal blast effect properly. Furthermore, progressive collapse mechanism of core structure which is one of the most important parts in high rise buildings is also analyzed using Autodyn. When internal blasts are loaded to core structure, the core structure is mostly damaged on its corner and front part of core wall from explosives. Therefore, if the damaged parts of core wall are demolished, progressive collapse of the core structure can be initiated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.3
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• pp.369-380
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• 2019

When a extreme loading such as blast is applied to prestressed concrete (PSC) structures and infrastructures for an instantaneous time, serious property damages and human casualties occur. However, a existing design procedure for PSC structures such as prestressed containment vessel (PCCV) and gas storage tank do not consider a protective design for extreme internal blast scenario. Particularly, an internal blast is much more dangerous than that of external blast. Therefore, verification of the internal blast loading is required. In this paper, the internal blast resistance capacity of PSC member is evaluated by performing internal blast tests on RC and bi-directional PSC scaled down specimens. The applied internal blast loads were 22.68, 27.22, and 31.75 kg (50, 60, and 70 lbs) ANFO explosive charge at 1,000 mm standoff distance. The data acquisitions include blast pressure, deflection, strain, crack patterns, and prestressing force. The test results showed that it is possible to predict the damage area to the structure when internal blast loading occurs in PCCV structures.

• Explosives and Blasting
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• v.38 no.4
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• pp.26-36
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• 2020

With the increase of expansion and use of the underground space, the possibility of an underground explosion by terrorists is increasing. In this study, after modeling a circular tunnel excavated at a depth of 50m, an explosion load was applied to the inside of the tunnel. As for the explosion load, the explosion load of the maximum explosive amount for six types of vehicle booms proposed by ATF (Bureau of Alcohol, Tobacco, and Firearms) was calculated. For the rock mass around the circular tunnel, three types of rock grades were selected according to the support pattern suggested in the domestic tunnel design. Nonlinear dynamic analysis was performed to evaluate the influence of the ground structure by examining the surface displacement using the explosion load and rock mass characteristics as parameters. As a result of the analysis, for grade 1 rock, the influence on the uplift of the surface should be considered, and for grade 2 and 3 rocks, the influence on a differential settlement should be considered. In particular, for grade 3 rocks, detailed analysis is required for ground-structure interaction within 40m. Also, it is considered that the influence of Young's modulus is the main factor for the surface displacement.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.101-109
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• 2018

Field experiments as well as numerical analyses with finite element analysis codes are two valuable and complemental ways to understand the structural response under explosive blast load. However, there seems to be only limited information available about finite element analysis and experimental validation on the response of structural components under internal explosions. For complementary use of the two ways, the numerical analyses should be validated with field experiments by comparing their results. In this paper, a small-scaled reinforced concrete building with a room is employed for experimental investigations. An amount of TNT is detonated at the center of the room. Pressure at three different sites in the room, displacement of centers of two walls, and damage patterns of four walls are measured and compared to results from numerical analyses. The experimental results are much similar to the numerical analyses results. The finite element analysis code ANSYS AUTODYN is employed to numerically analyze both pressure distribution inside the room and response of walls subjected to blast pressure. The feasibility and validity of the numerical analysis on the reponses of structural components under internal explosions are discussed in terms of structural damage assessment, and evaluated as the same damage in the analysis and the experiments.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.05a
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• pp.87-94
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• 1998

폭발현상(explosion phenomena)이 항상 연소(combustion)를 수반하는 것도 아니고, 연소현상이 항상 폭발적으로 일어나는 것이 아님에도 불구하고 많은 사람들은 폭발과 연소 사이에 밀접한 관계가 있는 것으로 생각하고 있다. 일반적으로 폭발이라고 하면 우선 큰 소리와 건물이나 실내의 파괴를 연상한다. 폭발 시에 발생하는 큰소리, 이른바 폭발음은 공기 중을 전파하는 압력파(blast wave)에 의한 것이고 건물이나 실내 파괴는 그들의 내부압력 상승에 의한 것이다. 그러므로 폭발현상은 압력상승과 불가분하다고 생각해도 된다. (중략)

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.89-95
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• 2016

Keeping the gas pipelines in the common utility tunnel is useful because it has a lower risk of corrosion than conventional burial, and can prevent from excavating construction. But, explosions in common utility tunnels can cause greater damage from the blast overpressure compared to outdoor explosions, due to nature of the confined environment. Despite this fact, however, research on common utility tunnels has been limited to fire hazard and little has been studied on the dangers of explosions. This study developed scenarios of methane gas explosion caused by gas leak from gas piping within the common utility tunnel followed by unknown ignition; the study then calculated the extent of the impact of the explosion on the facilities above, and suggested the needs for designing additional safety measures. Two scenarios were selected per operating condition of safety devices and the consequence analysis was carried out with FLACS, one of the CFD tools for explosion simulation. The overpressures for all scenarios are substantial enough to completely destroy most of the buildings. In addition, we have provided additional measures to secure safety especially reducing incident frequency.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.204-212
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• 2000

The waste ammunitions have been accumulated in excessive amounts these days. This study focused on the problems related to the method of ammunition disposal which leads the explosion inside the enclosure structure and controls the effects of detonation. This study enables us to design a new type of explosive disposal facilities that would fit to our environments. And this study gives us the prototype design of the explosive disposal structure that are explored in this research and will give us a chance to develop a new type structure that have not been devised by Army, and also will be applicable to construct a civilian explosive disposal structure located in airports, harbors, and public facilities.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.849-855
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• 2011

Emergency batteries on board are used for stairs, pathway lights, and emergency communications during alternator black-out. In addition, there are engine start-up batteries in lifeboats. Typically, these batteries are installed under the Classification Rules. However, Since batteries inside life boats are installed in a confined narrow space, it is difficult to perform regular maintenances. Also, even though there are air vents in the life boat, the temperature inside the life boat often reaches above $65^{\circ}C$, which is much higher than the regulation temperature, $45^{\circ}C$. In this paper, we will summarize the accident of battery explosion occurred in MMU training ship, and possible causes. We will propose preventive measures of battery explosions as well as the revision of the regulation.

• Bulletin of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.19-26
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• 2014

• Bulletin of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.27-31
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• 2014