• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.358-362
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• 2006

Pyro-shock generally refers to the severe mechanical transients caused by the detonation of an ordnance device on a structure. Such device on a structure, including linear explosive, and point explosive are widely used to accomplish in-flight separation of structural elements on aerospace vehicle. And they are a significant cause of launch vehicle failures. The launch vehicle being developed in Korea also uses the explosive for separation events. In this paper, the isolator equipped to small satellite launch vehicle made of PTFE(Teflon) is developed to reduce the separation shock. The test to measure dynamic stiffness of PTFE isolator is performed. This test enables us to find the frequency range of PTFE isolator. And,, pyre-shock test using explosive to evaluate the performance of PTFE isolator is executed. from this study, the isolator conformed to frequency range and load requirement is developed using PTFE instead of rubber.

• 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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• 2004.10a
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• pp.95-98
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• 2004

The present work has been developed the study of interpretation of separation behavior in gas expansion separation(GES) bolt which has the separation characteristic without fragmentation and minimum pyre-shock during the operation of the explosive bolt. In order to obtain the performance of minimum pyro-shock, the present work used non-compressive material instead of separation explosives. The use of the interpretation processor could be extensively helped to design the shape and the amount of explosives in the explosive bolt having complex geometry, and to analyse the separation behavior during the operation. It is also proved that the GES bolt is the most suitable the separation system necessary to minimum pyro-shock and non fragmentation compare to others.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1000-1005
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• 2003

The shock separation test simulates the environmental effects of the spacecraft separation from launch vehicle. The shock separation test for a structural model of KOMPSAT-Ⅱ(Korea Multi-Purpose SATellite Ⅱ) was performed in SITC(Satellite Integration ＆ Test Center) launch environmental test hall at KARI(Korea Aerospace Research Institute) to verify the shock test requirement of the spacecraft, to predict the induced acceleration responses on the primary structures and payloads by the explosion of pyre-lock and to perform mechanical fit check. The spacecraft with S/A was mated vertically to LV(Launch Vehicle) adapter simulator via a clamp band, then hoisted and suspended above a foam test bed by four isolation springs secured to the spacecraft hoist fittings to isolate the payload platform shock wave from the sling elements. For separation process, real pyre-devices were used and the time response signals from 60 accelerometers installed on the interested points was acquired and recorded. The SRS responses for each response channels were calculated and the achieved SRS's on the separation plane was reviewed and evaluated in comparison to the ICD(Interface Control Document) value.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.1
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• pp.27-34
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• 2005

The present work has been developed the study of interpretation of separation behavior in gas expansion separation(GES) bolt which has the separation characteristics without fragmentation and minimum pyre-shock during the operation of the explosive bolt. In order to obtain the performance of minimum pyre-shock, the present work used non-compressive material instead of separation explosives. The use of the interpretation processor could be extensively helped to design the shape and the amount of explosives in the explosive bolt having complex geometry, and to analyse the separation behavior during the operation. It is also proved that the GES bolt is the most suitable the separation system necessary to minimum pyre-shock and non fragmentation compare with others.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.3
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• pp.161-168
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• 2008

The deployable space structure is necessary to minimize the satellite volume and launch cost. For the deployment, passive deployment mechanism has widely been used to attenuate a latch shock induced when the structure is just fully deployed. To reduce the latch shock, viscous damper is applied to the passive deployment mechanism and it can control the deployment speed of the structure. In this paper, dynamic analysis of the deployable space structure using the passive deployment mechanism with the viscous damper has been performed. The viscous damping values have been optimized through numerical simulation. The satellite's attitude influenced by pyro activation for the release of the structure has also been investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.321-326
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• 2010

The non-explosive release device using jack mechanism is designed and fabricated for the small satellite. As a triggering actuator for the release device, a piezo rotory motor with torque of more than $1.7kgf{\cdot}cm$ is employed to guarantee stable activation. For performance tests of separation device, we conducted release time test, preload test and shock test. The device was operated within 1.172sec and activated stably under load of 45kgf. Maximum shock was measured as 18G that is much less than the pyro-separation device produces. We confirmed the possibility as a satellite separation device through above presented tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.923-928
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• 2008

Pyrotechnic shock or pyroshock is characterized as a transient vibration phenomenon which shows large acceleration and high frequency range up to 10kHz during the operation of separation devices where explosives are used. During the flight of a launch vehicle, pyroshock is mainly generated at several events such as satellite separation, fairing separation and stage separation. In this paper, wiremesh isolators are introduced and several types of isolators are manufactured for the performance tests. For the investigation of typical characteristics of wiremesh isolators, compressive loading tests are basically performed and pyroshock tests are accomplished to confirm pyroshock isolation ability of each wiremesh isolator by using 4Kg dummy mass.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.19-30
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• 2016

We presented a hydrodynamic modeling necessary to accurately reproduce shock-induced detonation of pyrotechnic initiator. The methodology for such numerical prediction of shock propagation is quite straight forward if the models are properly implemented and solved in a well-formulated shock physics code. A series of SSGT(Small Scale Gap Test) and detailed hydrodynamic simulation are conducted to quantify the shock sensitivity of an acceptor that contains 97.5% RDX. A TBI(Through Bulkhead Initiator) system, consisting of a train configuration of Donor(HNS+HMX) - Bulkhead(STS) - Acceptor(RDX), were investigated to further validate the interaction between energetic and non-reactive materials for predicting the detonating response for successful operation of such small pyro device.