• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.4
• /
• pp.269-275
• /
• 2020

An explosive bolt is one of many representative pyrotechnic release devices that separates two joined structures using explosives inside the bolt. In this study, a 1/2 inch ridge-cut explosive bolt with an EBW detonator was developed for usage in sled tests. The initial shape design was carried out based on the design method, and the performance test showed that the separation performance was outstanding but fragments occurred. Therefore, numerical analysis was performed to reduce the amount of debris by minimizing the amount of explosives. From the numerical analysis, the separation mechanism and characteristics of the ridge-cut explosive bolts were identified, and the minimum amount of explosives that does not generate debris was proposed. Verification tests revealed that the ridge-cut explosive bolts with the proposed explosive weight minimized fragments while maintaining the separation performance.

• Explosives and Blasting
• /
• v.19 no.3
• /
• pp.27-37
• /
• 2001

시가지 또는 중요한 구조물, 시설물 가까이에서 암반 또는 콘크리트를 파쇄해야 한 경우 제어발파공법 및 기계식 파쇄공법이 사용되고 있으나 기계식 파쇄공법은 발파보다 경제적인 효율이 다소 떨어진다. 따라서 도심지역에서는 제어발파의 발달과 미진동 및 저진동 발파방 법이 활용되고 있다. 그 방법 중에 주변 환경에 악영향을 미치지 않고 정적으로 파쇄를 실시 할 수 있는 방법으로서 (주)한화에서 개발한 뉴 화이넥카를 이용한 건설 토목현장에서의 실용성을 위하여 뉴 화이넥카의 개선 성능과 적합한 발파패턴을 제시하는데 목적이 있다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.2
• /
• pp.43-51
• /
• 2020

After the accelerated aging, the bulkhead initiator using high explosives was carried out to verify aging characteristics. The Thru-Bulkhead Initiator operates by transmitting shock-wave generated from micro-initiator to the acceptor and the ignition explosives through the bulkhead. In order to evaluate the life-time of the product, the accelerated aging condition was set according to the life-time, and the ignition performance of the sample was measured every 10 cycles by measuring the delay time and the maximum pressure through the 10cc closed bomb test. In addition, variance analysis was used to determine aging.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.4
• /
• pp.543-550
• /
• 2017

Various chemical properties including density and heat of formation of 1-substitued trinitroimidazoles (TNIs) were estimated by using density functional theory (DFT). Using chemical properties estimated by DFT, explosive performance and sensitivity of 1-substitued TNIs were analyzed by following the ADD Method-1 procedure. The results were displayed on two-dimensional performance-sensitivity plot, and were compared with those of explosive molecules commonly used in many military systems. Different 1-substituents of TNI made that both explosive performance and impact sensitivity were changed significantly. Methyl substituted TNI became moderately insensitive and slightly less powerful. Amino, fluoro, picryl, and difluoroamino substituted TNIs were highly powerful like RDX and HMX, but greatly sensitive. Nitro substituted TNI was predicted to be extremely sensitive to be handled as a secondary explosive.

• Explosives and Blasting
• /
• v.38 no.2
• /
• pp.13-21
• /
• 2020

The shaped charge was used in explosive demolition of a steel frame structure, but it was often not used because it was limited to use and impossible to supply at domestic and overseas. Existing linear shaped charge did not have sufficient cutting performance to cut steel frame structures with a huge scale and thick steel plate. To solve these problems, we produced a device that could generate metal jets using industrial explosives of high detonation velocity and pressure. In this study, we made a charging container of three types which applicable to explosive demolition of steel frame structures. The experiment of cutting performances was carried out to evaluate the effect of cutting of charging containers on the various thicknesses of the H-beam and steel plate. As a result of the experiment, sufficient cutting performance was confirmed.

• Explosives and Blasting
• /
• v.33 no.1
• /
• pp.1-12
• /
• 2015

In this study, the domestic bench blasting sites were researched to set the blast coefficient C according to the type of rock and type of industry. With the use of the experimental data on the representative industrial explosives and the data of the manufacturers'data on explosives, powder coefficient e was set up. The blast coefficient C was 0.21~0.30 when the average value for 5 representative kinds of rocks including granite was searched. The blast coefficient C for quarrying, mining and construction sites were 0.22, 0.13 and 0.26 respectively. On the other hand, powder coefficient e was obtained in four elements such as reactive energy, ballistic mortar test, VOD, Langefors'strength per unit weight. e value for emulsion which is one of the representative explosives was found to be 1 while those of high performance emulsion and ANFO were found to be 0.9 and 1, respectively.

• Explosives and Blasting
• /
• v.36 no.2
• /
• pp.10-18
• /
• 2018

The shaped charge is used in explosive demolition of steel frame structure, but it was often not used because it was limited to use or impossible to supply at domestic and foreign. To solve this problem, we needed a device that could generate matal jets using industrial explosive. In this study, we made a charging container, which metal jets were generated when explosives were detonated. Cutting performance tests were carried out to evaluate the effect of cutting of a charging container on a steel plate of 25mm thickness. In addition, we compared the results between the numerical simulation of penetration process and cutting performance tests and then was evaluated a cutting performance for steel plates of 35mm and 70mm thickness.

• Explosives and Blasting
• /
• v.25 no.1
• /
• pp.45-52
• /
• 2007

When emulsion explosives(1kg/cartridge) are loaded into a long vertical borehole at open blasting site, they undergo an Impact corresponding to 117.6J of shock energy. After shocking. the crystallization of emulsion nay happen immediately. Furthermore, it nay cause a desensitization, arising from increase in the density of emulsion explosive by the breakage of sensitizer. In this paper, some experimental work was performed using PVC pipe equipment(50mm diameter and 12m lengths) to investigate the effects of loading impart of emulsion explosive. It is shown that detonation energy decreases up to 26% of the normal state value and this effect is less than 3% of the total performance of emulsion explosives in borehole blasting.

• Corrugated packaging logistics
• /
• no.62
• /
• pp.25-30
• /
• 2005

성능인증 제도란? 중소기업이 개발한 기술개발제품을 지방중소기업청 또는 시험연구원에서 그 성능을 검사하여 성능이 확보되었음을 인증하는 제도로써 중소기업이 생산한 기술개발제품을 공공기관에서 안심하고 우선구매토록 정부가 성능을 확인하는 제도이다. 중소기업이 개발한 기술개발제품이면 성능인증을 신청할 수 있으며, 다만, 의약품, 농$\cdot$수산물, 총포, 화약류, 사행성 제품, 비가공 제품 식$\cdot음료품은 제외된다. 신청은 중소기업청에 접수하며, 지방중소기업청에서 신청을 받으면 지방청에서 성능검사가 가능한 사항은 지방청에서 직접 성능검사를 수행하고, 지방청에서 불가능한 일부 항목에 대해서는 시험연구원에 위탁하게 되며, 시험연구원은 성능검사 결과를 지방청에 제출하면 지방청은 그 결과를 토대로 성능인증을 하게 된다. 성능보험제도란? 성능인증을 받은 제품을 공공기관에 납품한 후 성능저하로 인한 손해를 보전해주는 제도로써 구매담당자가 성능보험 가입제품을 구매하여 사고가 나더라도 면책될 수 있으며, 성능보험 가입제품은 제한 또는 지명 경쟁에 우선 입찰할 수 있는 자격을 부여해 준다. 가입은 성능인증을 받은 제품이 성능보험에 가입할 수 있으며, 의무보험이 아닌 임의보험이므로 반드시 성능보험에 가입하지 않아도 된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.340-343
• /
• 2011

Explosive bolts are reliable and efficient mechanical fastening devices having the special feature of a built-in release. The disadvantage of explosive bolt lies in that it is based on the high explosive effect of a pyrotechnic charge. The aim of the present work is to propose a pyrotechnically releasable mechanical linking device for two mechanical elements that does not suffer from such drawbacks. The pyro-lock using the pressure cartridge has the release characteristic without fragmentation and minimum pyro-shock. The present work is focused on the design, the interpretation of structure, the separation mechanism, separation force, and the results of various tests.