• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.2
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• pp.213-220
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• 2017

Pyroshock produced by the pyrotechnic devices can induce failures in nearby electronic devices. To handle and mitigate pyroshock inducing problems, appropriate measurement of pyroshock is essential. In this study, pyroshock measurement technique is established using laser Dopper vibrometers (LDVs) and shock accelerometers. Pyroshock produced by the explosive bolts and the pyrotechnic initiators under various environments is measured. The characteristics of pyroshock including the effects of supporting structures, propagation form on thin plate, sensor (contact and non-contact) types are discussed.

• Journal of the Korean Society of Systems Engineering
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• v.4 no.2
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• pp.35-43
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• 2008

Application of system engineering should be realized on necessary condition being to propel National Defense R&D Program. But, these necessity is yet not realized easily to many project managers of Defense Acquisition Program Administration(DAPA). As one person of DAPA project manager, system engineering hard to approaches easily by the word itself. There are a lot of difficult sections where should apply how. This paper established DAPA Project Manager and Acquisition Point of Contact of demand Military by main customer (reader), and wished to make understood more easily and approach system engineering application to these. Also, this paper studied project management example that scientific project management techniques of Earned Value Management(EVM) and Cost As an Independent Variable(CAIV) etc. is taken abuzz in DAPA inside by Project management technique that become reform, arc Integrated in system engineering.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.69-73
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• 2011

In the defence wireless communications, conventional Anti-Jamming techniques(Frequency Hopping/Spread Spectrum or Direct Sequence/Spread Spectrum) are used to overcome a intentional interfering signals which are single/multitone or partial band jammer etc. DS/SS techniques is very strong on tone jamming signal but not to be on a partial band jammer. So FH/SS AJ performances are expected method of an substitution of DS/SS, however FH/SS could not have good performance on some BMTJ(Band Multi-tone Jammer). So this paper proposes FH-CSS (Frequency Hopped - Chirp Spread Spectrum) to get more robustness against jammers(BMTJ, PBNJ) and analyze the AJ performances.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.84-89
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• 2016

THPP(Titanium Hydride Potassium Perchlorate) is an igniter composed of potassium perchlorate as oxidizing agent and titanium hydride as fuel with a Viton binder. THPP is commonly found in the aerospace, defence and automotive industries. This research is investigeted for the manufacturing process and characteristics analysis of the THPP such as the performance and shape/calorimetry/pressure characteristics of the THPP on PMD(Pyrotechnic Mechanical Device). Also, THPP composite ratio is designed by CEA program.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.5
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• pp.654-662
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• 2014

In the development of the weapon systems, utilization of Modeling & Simulation is growing in every aspect of development process. For the higher utilization of M&S, reuse of the M&S resources is needed to reduce the cost of M&S. I propose the M&S architecture framework that can enhance the reusability of the M&S resources in developing surface-to-air weapon systems. This M&S architecture design framework enables interoperability between the system and sub-systems. In this paper, the advantage and the necessity of the M&S architecture design framework will be described by introducing the cases that the M&S architecture framework reused in the combat experiments, the system development tests, the system operational tests and the concept developments in real projects. These cases will show the high reusability and efficiency of the M&S architecture design framework.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.58-67
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• 2020

In this study, finite element fatigue analysis combined with a fatigue correlation factor is proposed to predict the bending fatigue life of a gear in an electro-mechanical aircraft actuator. First, stress-life curves are obtained for the gear material via a round bar fatigue test. Subsequently, stochastic stress-life (P-S-N) curves are derived for 50% and 1% failure probabilities, separately. The curves are applied to the fatigue analysis model of a single gear tooth, and the effect of the fatigue correction factor is analyzed. The analytical P-S-N curves reflecting the fatigue correction factor matched the experimental data. This shows that the analytical fatigue life is reliable and that the analysis technique is effective.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.91-99
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• 2020

This study proposes a finite element (FE) model for predicting the bending strength of small gears used in electro-mechanical actuators for aircraft. First, a strain gauge was attached to the tooth root of test gear, and the strain was measured. Subsequently, the FE model was applied to calculate the strain of the test gear, and the modeled strain was compared with the experimental strain. The results confirmed that the FE strain was very close to the experimental strain and the FE model was valid. This FE model was extended to the bending strength analysis of several small gear tooth models. The bending strengths of all the tooth models were almost identical to the ISO theoretical bending strength. Finally, the FE model was validated and the reliability of the modeled bending strength was evaluated through the strain measurement experiment.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.58-67
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• 2021

This paper describes the development for the dual thrust rocket motor with two types of propellants with different combustion characteristics. We developed the composition of two kinds of propellant to be applied to a rocket motor, and improved a propellant charging process in a free grain type to improve the adhesion method and the problems of adhesion between different propellants. In addition, to meet the ignition phenomenon as a small rocket motor, the ignition delay was improved by applying a nozzle plug developed in a high density foam. The propulsion rocket motor reflecting this design and the improved manufacturing process was evaluated through a ground performance test.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.11-17
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• 2016

BTTN and TMETN are representative energetic plasticizers used for various propellants. However these compounds are sensitive relatively. So, in order to develop insensitive energetic plasticizer, this study attempted to synthesize derivative of triazole, 4,5-bis(azidomethyl)-(2-methoxyethyl)-1,2,3- triazole (DAMETR). Also, the prepared compound was characterized by NMR, IR spectroscopy, and physicochemical properties such as glass transition temperature, melting point, decomposition temperature, density, viscosity and impact sensitivity. In addition, the heats of formation (${\Delta}H_f$) and detonation properties (pressure and velocity) of DAMETR were calculated using Gaussian 09 and EXPLO5 programs. Especially, 1-DAMETR(>50 J) was more insensitive than BTTN(1 J) and TMETN(9.2 J).

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.223-230
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• 2018

This study analyzes the cost fluctuation between cost in contract stage and cost in adjustment stage in defense R&D project. This research shows that certain costs hold with the cost fluctuation and their degree of influence. The results of first analysis show that 13 out of 17 costs have a relationship with the cost fluctuation. The estimate of direct labor cost is positive and significant at the 0.1% level(direct labor = 1.022, t = 38.355). The estimate of amount of cost paid to subcontractor is positive and significant at the 1% level(amount paid to subcontractor = 0.942, t = 51.894). The results of second analysis show that all the direct costs have a relationship with the cost fluctuation(The fact that cost system is focused on direct labor cost is a consideration in this analysis). The estimate of direct labor cost is positive and significant at the 0.1% level(direct labor = 2.014, t = 21.787). The estimate of amount of cost paid to subcontractor is positive and significant at the 0.1% level(amount of cost paid to subcontractor = 1.068, t = 15.636). This finding supports a proposal theory that cost system is focused on direct labor cost through actual proof analysis and an inducement that amount of cost paid to subcontractor is a way to reduce the R&D cost.