• Korea Trade Review
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• v.44 no.3
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• pp.85-104
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• 2019

As exporting countries are limited compared to the export market of civilian industries, an approach should be preceded by a comprehensive evaluation of the purchasing availability of exportable markets and the status of potential competitive markets, as well as an analysis of the technology related to weapons systems. Based on the case of K9 self-propelled howitzers, a leading overseas export weapons system, this research was conducted to clarify the process of selecting the export market for Korean defense products and to verify it using a survey of weapons systems experts. In particular, this study specifically suggested the methodology needed to select the final exportable market through the analysis procedures such as competition and similar weapons systems, key performance identification, and identification of export-oriented markets, while considering the characteristics of the Defense Industrial Products. Based on these analysis results, the government proposed a method of selecting a major export market to enhance the possibility of weapons exports by domestic defense companies. Therefore, the study results can be used as a basis for objectively assessing the priorities for exportable markets, considering the possibility of exporting weapons systems that are under research and development or will be improved in the future.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.6
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• pp.553-560
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• 2022

This study investigates improvement of torsional strength of special wrench for K-series self-propelled howitzer power-pack maintenance. In order to maintain the power-pack, special wrench is one of the essential tools for assembling/disassemblimg the engine and transmission. However, failures(plastic deformation, fracture phenomenon and etc.) have been frequently reported even though special wrench was used within recommended standard torque range. Therefore, in this study, finite element analysis using ABAQUS was performed and modification of design parameters have been proposed. Prototypes based on the proposed parameters were manufactured and torsional experiment(torque about 130 % of recommend maximum torque) validated the newly proposed design parameters. Special wrench based on this study is applied to mass production and currently used for the maintenance.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.195-203
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• 2010

This paper concerns about total dynamic analysis of integrated mining system. This system consists of vertical steel pipe, intermediate buffer station, flexible pipe and self-propelled miner. The self-propelled miner and buffer are assumed as rigid-body of 6-dof. Discrete models of vertical steel pipe and flexible pipe are adopted, which are obtained by means of lumped-parameter method. The motion of mining vessel is not considered. Instead, the motion of mining vessel is taken into account in form of various boundary conditions (e.g. forced excitation in slow motion and/or fast oscillation and so on). A terramechanics model of extremely cohesive soft soil is applied to the self-propelled miner. Hinged and ball constraints are used to define the connections between sub-systems (vertical steel pipe, buffer, flexible pipe, self-propelled miner). Equations of motion of the coupled model are derived with respect to the each local coordinates system. Four Euler parameters are used to express the orientations of the sub-systems. To solve the equations of motion of the total dynamic model, an incremental-iterative formulation is employed. Newmark-${\beta}$ method is used for time-domain integration. The total dynamic responses of integrated mining system are investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.384.2-384.2
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• 2016

Recent publications reported the self-propelled jumping of coalescing dew droplets on superhydrophobic surfaces [1-2]. We further investigated the initial growth, coalescence, and removal by self-propelled ejection of nano and microscopic water droplets on the superhydrophobic surface of lotus leaves under condensing conditions. By using a high-speed digital camera mounted on an optical microscope, we have found: (1) sub-micrometer droplets form and grow on nanoscale waxy hairs; (2) growing droplets coalesce rapidly upon contact, but never jump off the surface unless the diameter of merged droplets exceeds ${\sim}15{\mu}m$; (3) the diameter and direction of jumping droplets are very narrowly distributed, centered at $20-30{\mu}m$ and ${\sim}20$ degrees from the surface normal, respectively. We present a rationale for these observations on the basis of: (a) the hierarchically rough surface structure on nano- and micro-scales; (b) its chemical composition; and (c) the balance among competing forces of cohesion (surface tension), adhesion and gravity.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06a
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• pp.12-16
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• 1996

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.142-145
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• 2002

In order to develop a self-propelled microendoscope, the frictional resistance of the capsule-type endoscope inside the intestine should be understood. In this work the frictional resistance behaviors of capsules with different designs were experimentally investigated using a pig intestine. It was found that cylindrical capsule design had the least frictional resistance. Also, the resistance increased as the speed of the capsule motion was decreased. It is expected that the results of this work will be used to design the optimum propulsion system for the microendoscope.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1910-1920
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• 1993

An experimental study to investigate the unconventional chip formation called triangulation of chip in cutting with a SPRT (self-propelled rotary tool) is performed using acoustic emission (AE) signal analysis. In doing that, a quantitative model of the AE RMS signal in triangulation with a SPRT is first developed. The predicted results from this model show good correlation between the AE RMS signal and the general characteristics of triangular chip formation. Then, effects of various process parameters such as cutting conditions (cutting speed, depth of cut, oblique angle and normal rake angle) and the work material properties on the chip formation in cutting with a SPRT are explored. Special attention is paid to the work material properties which are found to have significant effects on triangulation.

• Journal of Forest and Environmental Science
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• v.25 no.1
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• pp.75-84
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• 2009

This study was conducted to investigate the physical properties of wood chip for fuel processing with woody biomass. Seven species are selected and processed for testing physical properties by 3-type wood chippers which are commonly used in Korea. Wood chips produced by self-propelled drum chipper and fixed type wood chipper equipped with separator were uniform in size and shape. It was shown that the bulk density of produced wood chips was decreased with increasing the wood chip layer thickness, and oak chips prepared by self-propelled drum chipper and fixed type wood chipper showed the highest bulk density.

• Journal of the military operations research society of Korea
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• v.31 no.2
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• pp.75-85
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• 2005

Even though K-series combat equipment's engine depot maintenance cycle of ROK army is 10years In average, that of the K-9 Self Propelled(SP) howitzer which has been fielded since 99 $3{\sim}4$years causing limitations to effective equipment operations and combat-readiness. Therefore, the current K-9 self-propelled howitzer engine operation period of 1,500 hours, which is greatly shorter than other equipments, had to be verified. In order to find the optimum depot maintenance cycle, related field operation conditions were verified and opinions were collected, and also the background on current depot maintenance cycle setting was studied.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.139-147
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• 2016

This study described the design scheme for each step of the production test for the Fire Control System(FCS) of the K-55A1 PIP business of Hanwha Thales since 2011. From the time of receipt of the product It is necessary to improve the FCS's reliability by using the Unit Test, burn-In test, System Test. FCS of K-55A1 acts as a 'head' that control the self-propelled howitzer, and connected with the electrical and physical connection of self-propelled howitzer's multiple unit (Inertial navigation systems(IN), Muzzle Velocity Radar (MVR)) for the normal operation without an inch of error in operating. We designed the production testing equipment automatically as much as possible and designed with the environment similar to the self-propelled howitzer. by using this production testing equipment, It should help for the strengthen national defense of the Republic of Korea.