• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.67-74
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• 2016

Explosive bolt is one of separation device that uses high explosive charge, and is separated by pressure formed by an explosion and the resulting shock waves. Explosive bolt having such a mechanism would have to be designed to minimize shock and debris formation generated during separation. In this study, separation tests were carried out with distance as variable for restraining the explosive bolt (Air Gap). Bolt release and its separating shape with variation of air gap is observed, and we used accelerometer to measure the shock wave transmitted through a bound object. In addition, separation behavior of explosive bolt is analyzed using ANSYS AUOTODYN program. By comparing the results of previously performed experiments and analysis, we could confirm the effects of air gap to the release behavior of explosive bolt, and decide optimum constraining environment for specific separation bolts.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.84-90
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• 2017

Explosive bolt is coupled in a variety of guided weapons and space projectiles, to perform the separation function. Thus, the role of the explosive bolt in guided weapons systems is very important, as it can cause failure of the entire system in the case of mission failure. For this reason, the design life prediction for explosive bolt is highly and frequently required recently, but its accurate prediction method has not been presented. In order to apply the existing accelerated aging process, we should know the activation energy and the acceleration factor of the explosive bolt. Since the information required for accelerated aging is not presently secured, it is difficult to predict the design life of explosive. Thus, in the present study, we have evaluated the performance of actual explosive bolts in the condition of natural aging over 10 years in order to present a minimum design life.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.92-95
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• 2005

The present work has been developed the type of non-electric and delay explosive bolt which does not need power supply device and has the delay function in the operation of the explosive bolt. Separation device system could be minimized because of non-electric power supply system. In order to prove the mechanism of operation, the present work used to ignite the initiator the power of air resistance caused front aviation object. we can be founded from the present work that the changes in the operation load influence directly the ignition of the initiator. The design of non-electric and delay explosive bolt is the most suitable the separation system necessary to reduce the velocity of aviation object and safe landing of parachute system.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.60-65
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• 2005

The present work has developed non-electric and delay-type explosive bolt that does not need electric power supply device and has the delay function in the operation. Non-electric power supply system enables separation device system to be minimized. In order to prove the mechanism of the operation, the power of air resistance caused from aviation object used to ignite the initiator. we can be founded from the present work that the changes in the operation load influence directly the ignition of the initiator. The design of non-electric and delay type of explosive bolt is the most suitable for the separation system that is necessary to reduce the velocity of aviation object and safe landing of parachute system.

• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.243-246
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• 2006

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyre-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyre-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.179-182
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• 2008

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyro-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.293-296
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• 2008

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems, it has been invented ball type bolt. The present work was represented quantitively the margin of separation safty and separation mechanism in ball type bolt to analyse the dynamic separation test. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyro-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.173-176
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• 2005

The present work has been studied the reliability improvement of inspection method for explosive bolt body. The standard value of impact test is made from impact test of explosive bolt body and a useful data is established to the correlation between the hardness and impact data of bolt body. The method is overcome an error obtained from conventional inspection by analysing the mechanical data from each inspection and can be improved to the reliability when mechanical property of explosive bolt body is inspected.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.208-211
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• 2007

Separation Devices have two functions. These two functions are to bond and to separate two bodies. This paper is about separation devices which use explosives to separate their bodies. Explosive bolt is separated with two bodies when the explosives in the body detonated. The good things of explosive bolt are that it has simple operational system and it is made of few parts. But it has side effects; fragment and pyre-shock. To avoid these side effects gas expansion separation(GES) bolt and pressure cartridge actuation separation(PAS) devices are invented. These use pressure to separate their bodies. The pressure is generated when explosives are burned. But the sizes of PAS devices are bigger than explosive bolts. And GES bolt has a mechanically lower bonding ability than that of explosive bolt. When you design separation devices, it is recommended to know operational system and characteristics of separation devices, to design best one.