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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Institute of Military Science and Technology
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The Korea Institute of Military Science and Technology
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Volume & Issues
Volume 4, Issue 2 - Dec 2001
Volume 4, Issue 1 - Jul 2001
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A study on the shock ＆ vibration characteristics of a tractor-trailer type vehicle system running on the road
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 13~19
It is known that displacements, velocities and accelerations of the tractor- trailer type vehicle system in shock & vibration analysis by the flexible-multi-body dynamics including the flexibility of structure are bigger and more repetitive than them by the rigid-multi-body dynamics, and it is necessary to prove above results by the experimental field test. Therefore, in this paper, theoretical analysis by the flexible-multi-body dynamics and experimental field test for a tractor-trailer type vehicle system are conducted and their results are compared with each other. Because of unexpected metal contact and impact in the air coupler part in the field test, some accelerations measured from the experimental field test are bigger than them analyzed from the theoretical analysis, but most accelerations are well coincide with each other in the amplitudes and trends. Thus more refined dynamic analytical models for some special type vehicle systems will be possible in the future.
A study on friability test to assess the mechanical impact sensitivity of insensitive explosives
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 20~29
We recently developed a friability test procedure, which will be used as one of substance tests for Extremely Insensitive Detonating Substances(EIDSs) in Test Series 7 of the United Nations. This test was intended to assess the susceptibility of insensitive explosives to the break-up as high strain rate and subsequent ignition characteristics of the deformed material. We designed an air gun system using the hydro code simulation. The projectile velocities of the gun were in good agreement with those predicted by the hydro code with an inert material. Three different types of explosives, melt castable Comp B, castable plastic bonded explosives(PBXs), and pressable PBXs were tested during the development of the test procedure. Two tastable PBXs, i.e. DXD-09 and DXD-10, which are currently under development as candidate formulations of EIDS were classified as EIDS, since test results with these formulations were far better than the criterion of the UN Test Series 7.
A Study on the Aperiod Bearing Only TMA
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 30~40
This paper presents a study on the design and simulation of bearing only target motion analysis to enhance the TMA capability using SONAR in underwater environment. A bearing only target motion analysis algorithm using aperiod bearing input signals has been developed and simulated in the MATLAB.
Dynamic Performance Simulation of Diesel Engine for Underwater Vehicle
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 41~51
In this paper, the mathematical modeling and the design of controllers were performed for the dynamic performance simulation of the diesel engine for underwater vehicle. Nonlinear equations are acquired through the mathematical modeling using mean torque production model technique. Three kinds of controllers were designed for the perform simulation of the engine model. As the result of simulation, it was confirmed that each controller can be applied with regard to system characteristics and desired conditions etc.
A Study on the Control of a Cable Spooling System for Towed Array Handling Winch
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 52~61
The purpose of this paper is to study on the control of a self-activated cable spooling system for towed away handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specfications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.
Development of the CAD Modelling System for the Submarine Digital Mockup
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 62~72
In the countries of USA, UK, etc, which have the advanced submarine design technologies, the digital mockup actively applies in the naval ship and the submarine design, because it has many advantages such as the reduction of shipbuilding periods and costs, the potential of easier design changes, the combination of visualization with realistic behavior and so on. This paper includes the architecture development methods of digital mockup system and presents the S/W and H/W architecture scheme and the methods of 3D CAD modelling system of a submarine hull and machineries for the conceptual design verification.
Laying control of a submarine cable
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 73~82
In this Paper, slack is computed from a comparision of the cable pay out rate and the ship ground speed in accordance with laying conditions, and the speed controller of the cable engine based on an
servo control is designed for adjusting the cable engine in order to lay a desired amount of slack. The controller is designed to have the robust tracking property of the cable engine under disturbances. The performance of the designed controller is evaluated by computer simulation, and, consequently, a feasibility study for laying the submarine cable stably is done through analyzing simulation results.
A Study on the gain and phase matching between channels in the Monopulse Receiver
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 83~92
In this paper, the monopulse channel receiver which can be matched between channels through a wide bandwidth has been proposed. The effects of the gain and phase imbalance between channels on the slope of monopulse error signal were analyzed. Also, the matching method between channels in a wide bandwidth was proposed, by which monopulse slope could be stabilized. Using the implemented monopulse radar system the monopulse slope was measured in the anechoic chamber which include the moving horn antenna and the target signal generator. The results show that the wide band matching method is useful and applicable to various channel receivers
A Comparative Analysis of Target Strength Estimated Models for Underwater Echo Signal Synthesis
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 93~103
A reflection signal in an active sonar using a high frequency is mainly formed of a specular reflection from the surface of an object along with several equivalent scatters inside, which are characterized by the spatial distribution of the highlight on the object. This study analyze the existing echo signal synthesis models eq, random distribution model, equivalent interval distribution model & MUTAHID(Modified Underwater TArget by HIlight Distribution) model for simulated target, and compare the characteristics of the reflected signal synthesis results for each model in various conditions. These highlight distribution models can be efficiently applied to the simulated target signals synthesis of various real systems requiring the echo signal synthesis on the underwater target.
Performance Analysis in Wide Swath Mode on a Spaceborne SAR System
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 104~123
Synthetic Aperture Radar(SAR) can provide radar imagery in all weather, day and night situations. Recently SAR system consisted of several imaging modes, has been used for not only military purpose, but also commercial and scientific applications. This paper firstly reviews spaceborne SAR theory, specially scansar principle, and secondly the theories and the design procedures of system performance analysis in the scansar mode, which are different from the ones in the conventional stripmap mode. Based on the SAR-related knowledge, it lastly derives the results of performance analysis in wide swath mode using the scansar technique at the design phase. It shows that these results can meet the system requirements as given the customer. In future, they will continuously be updated using the real measurement data, in connection with the development of a spaceborne SAR system.
The Design and Manufacture of Ku-Band Circular Waveguide with Circular Polarizaed Wave Characteristic
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 124~136
In this paper, we designed and manufactured the Ku-band circular waveguide antenna to do wireless communication with a ground radar as on-board antenna of missile. Using the MATLAB and the HFSS, we designed the circular polarizer which has a characteristic of circular polarization and broadband using the capacitive pin method, the feeder to feed coaxial line to circular waveguide, and a stopper to prevent a conductor material from being inserted. Then we simulated the designed antenna using the HFSS, obtained the gain and the radiation pattern. Because of a difficulty of manufacture, we established a manufacture process procedure. Antenna is manufactured with this procedure, test results of the manufactured antenna are the axial ratio of 1.37 ~ 1.72, the 3 ㏈ beamwidth of
and the gain of 3.26 ~ 4.61 ㏈ within frequency band. We knew that these results are similar with simulation results. Also, we confirmed that the manufactured antenna is satisfied with requirement conditions through performance test, environmental test and flight test.
A study on the developmental method of parachute and air stabilizer for light weight torpedo
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 137~146
According to the advanced development of Light Weight Torpedo, the overall items related with the parachute type and gore layout and air stabilizer of the parachute for fixed and rotary wing aircraft are described in this paper. Also, the drag-area which should satisfy the firing envelope, parachute inflation characteristics, stability of parachute and torpedo in airdropping, water entry impact on torpedo and parachute constituted the principle design factors. The important trial and errors occurred in the step of performance of the parachute for fixed and rotary wing aircraft are investigated and analyzed.
Shock Test Signal Analysis using Wavelets
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 147~154
The underwater explosion shock test is performed for the evaluation of the shock-resistant capability which is a very critical factor considering the survivability of the battle ship. Some measured signals have impulsive noise and gaussian white noise because of the unstable power supply system and the transient movement of cables during the underwater explosion shock test. The advanced shock signal analysis method which remove the noise of measured signal using the threshold policy of the median filter and the orthogonal wavelet coefficients are proposed. It is verified that the signal-to-noise ratio was improved about 30㏈ by the numerical simulation.
Development of Dynamic Pressure Calibrator with Positive Step Pressure
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 155~169
In this paper, dynamic pressure is mainly generated in the closed chamber of gun when the propellant is fired and has exponential pressure motion. Dynamic pressure calibrator with positive step pressure was designed and manufactured to meet the calibration of piezoelectric high pressure transducers which are mainly used to measure dynamic pressure motion in the test of weapon systems. In addition, the results of Performance test and analysis of system uncertainty are provided.
Optimum Replacement Intervals Considering Salvage Values In Random Time Horizon
Park, Chung-Hyeon ; Lee, Dong-Hoon ;
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 170~176
An optimization problem to obtain the optimal replacement interval considering the salvage values is studied. The system is minimally repaired at failure and is replaced by new one at age T(periodic replacement policy with minimal repair of Barlow and Hunter〔2〕). Our model assumes that the time horizon associated with the number of replacements is random The total expected cost considering the salvage values with random time horizon is obtained and the optimal replacement interval minimizing the cost is found by numerical methods. Comparisons between non-considered salvage values and this case are made by a numerical example.
A Study on the Radiation Pattern Measurement Technique of Shipboard Antenna
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 177~187
It is important to test and evaluate the variation degree of ship-mounted antenna radiated power with respect to all directions in order to use more effectively antennas that installed on naval ships. The naval ship has various sensors for navigation, communication and electronic warfare, etc. And the performance of these sensors extremely depends on the various characteristics of antenna system to transmit and receive electromagnetic wave. The radiated power pattern of the antenna differs from all aspect angles of the ship because of complex superstructures. It is important to know the weak point(direction) of antenna radiation for appropriate operation. Therefore, the ARP(Antenna Radiation Pattern) of shipboard antennas is measured for the all aspect angles. The results of ARP measurement are utilized as reference for antenna arrangement of newly-built same class warship. This study also describes the development results for the ARP measurement technique, software design and test procedures to measure the radiation pattern of communication equipment antennas using the fixed test site.
Subcloning and Expression of a Gene Encoding an Organophosphorus Acid Anhydrolase
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 188~197
Organophosphorus acid anhydrolases(OPAA) catalyzing the hydrolysis of toxic organophosphates have been found in a variety of prokaryotic and eukaryotic organisms. Of the several kinds of OPAA that can degrade nerve agents, such as DFP, sarin and soman, a OPAA gene harbored in the chromosomal DNA of Alteromonas haloplanktis strain was subcloned in order to develope an enzymatic degradation method of toxic organophosphorus compounds. For this 1481 bp DNA fragment containing OPAA gene and its flanking regions has been synthesized through PCR using chromosomal DNA of A. haloplanktis strain. After subcloning and subsequent expression, crude OPA anhydrolase was prepared and assayed. It was shown that the OPAA had a very high hydrolytic activity on DFP. The specific activity of the enzyme was 1,110
protein. It seemed that OPAA with such a high hydrolytic activity may give a good prospects to its use, as a biodegradation tool, in detoxifying toxic organophosphorus compounds, such as pesticides and chemical stockpiles which are posing a potential threat to the field environment and human health.
Structure of Yb Complex with 3-nitro-1,2,4-triazol-5-one
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 198~206
The structure of Yb complex with 3-nitro-1,2,4-triazol-5-one(NTO),
has been investigated by X-ray diffraction method. Crystallographic data for the title compound : monoclinic, C2/c,
The intensity data were collected on a Broker SMART diffractometer equipped with a CCD area detector using Mo
radiation. The structure was solved by direct method and refined by full-matrix least-squares calculations to a final R value of 0.0424 for 4727 independent reflections and 335 parameters. The three carbonyls of three NTO anions and four ligand water molecules which are formed the pentagonal bipyramid are coordinated with
and also five water molecules are included in the form of the crystal water in the molecular structure.
Analysis of surface interaction between filler and binder of PBXs
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 207~215
Plastic bonded explosive(PBX) is mainly composed of the nitramine-ploymer compositions. PBX is characterized by high velocity and pressure of detonation, low vulnerability and good thermal stability. Many important applications of PBX require the good adhesion between nitramine crystals and the binder. For PBXs as well as propellants, where good mechanical properties are of great importance, dewetting therefore must be prevented by strong adhesion between filler-binder. Adhesion depends on surface characteristics of filler and binder. In order to design for better adhesion, an understanding of the surface properties of explosive and binder is required. The surface free energies are calculated from contact angle values by the method of Kaelble. Critical surface tension of solids are calculated by Zisman plot. Critical surface tension is a useful parameter for characterizing the wettability of solid surface. In this study, HMX and 3 kinds of copolymers are selected, since they are widely used in many plastic bonded explosives. The technical objective of this investigation is to predict the interaction between filler and binder from their surface free energies
A Crystal Type Conversion Study of HNS(Hexanitrostilbene)
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 216~224
HNS(hexanitrostilbene), one of the most important heat resistant explosive was recrystallized using organic solvent, nitric acid and dual solvent system of acetonitrile-toluene. The purification, analysis, type conversion method and its physical properties are described.
A Transfer Alignment Considering Measurement Time-Delay and Ship Body Flexure
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 225~233
This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. Specifically, to reduce alignment errors induced by measurement time-delay and ship body flexure, an error compensation method is suggested based on delay state augmentation and DCM(Direction Cosine Matrix) partial matching. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then DCM partial matching is properly combined to reduce effects of a ship's Y axis flexure. The simulation results show that the suggested method is effective enough resulting in considerably less azimuth alignment errors.
Maxima Response Spectrum for each Mechnical Vibration and its Application
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 234~245
This paper considers the Maximum Pesponse Spectrum for the random vibration, sinusoidal vibration, linear sweep vibration. The random vibration quality levels and the sinusoidal vibration quality level are compared using MRS. And the severity between the vibration test specification and real environments using Maximum Response Spectrum are also compared using it.
A Study on the Reduction of Stress Concentration for the Breech System
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 246~254
The breech system can be considered as a pressure vessel with an internal plug under high explosive pressure. The system consists of a breech block(internal plug) whose front surface subjects to pressure, and a breech ring(pressure vessel). There is the geometric discontinuity around roots of connection parts and then stress concentration is introduced due to pressure, where contact effect may be ignored because contact plane between two equipments is parallel ideally, Generally high stress concentration phenomena shorten the life cycle of the mechanical system. It is well known that shock load is much more harmful on safety of the system than static load. In this present paper, several geometric design variables which may affect stress condition on the system are chosen and the parametric study on the design variables is carried using commercial FEM codes. Finally, the obtained results in the single lug breech system are applied to design the 3 lugs breech system. The 3 lugs breech system can reduce the maximum stress level.
Strength Characteristics of An Aluminum 2024-T3 in Short-time High Temperature Environment
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 255~263
The main purpose of this paper is to investigate strength characteristics of Aluminum 2024-T3 in high temperature environment. Tensile test of Aluminum 2024-T3 has been carried out in high temperature environment. The stress-strain relations are investigated with temperature and Young's modulus, yield strength and ultimate strength are deduced from the test results. The modulus and strength of the test are compared with those of MIL HANDBOOK and tips on structural design in high temperature environment are suggested.
Cooling effect of an electronic module with a variation of the inlet air temperature
Journal of the Korea Institute of Military Science and Technology, volume 4, issue 1, 2001, Pages 264~273
The conjugate heat transfer from a protruding module in a horizontal channel with a variation of air temperature is experimentally investigated. It is an aim of this study is to estimate temperature difference between a module and air. This study is performed with a variation of parameters that are air temperatures(
air velocities (
m/s~l.5 m/s ), and input power (Q=3 W, 7 W ). The results show that as the thermal resistance increases, the effect of air temperatures are decreased. And input power was most effective parameter on the temperature difference between a module and air.