• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.688-696
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• 1995

Cemented carbides, best known for their superior mechanical properties such as high strength, high hardness and high wear resistance, have a wide range of industrial applications including metal working tools, mining tools, and wear resistance components. The cobalt has been used as a binder in the WC-based hard composites due to its outstanding wetting and adhesion characteristics even though its expensiveness. Therefore many studies attempted to find a better substitute for cobalt as binder to decrease production costs. This investigation is a pre-step to study dynamic fracture characteristic evaluation of a WC-Co hardmetal were evaluated by using the instrumented Charpy impact testing procedures. It was found that the dynamic characteristics of used strain amplifier were very important experimental factors to extract valid dynamic fracturing data in WC-Co specimens. It was suggested by showing some experimental examples that when we wished to evaluate dynamic fracture toughness for cemented carbide composites by using the instrumented Charpy impact testing procedure, a careful attention must be given to obtain valid results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.219-223
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• 2006

This paper presents a gantry type 3-axes positioning system, which is useful to test control algorithms for coordinate measuring machines and industrial cranes. The dynamic characteristics of the system have been investigated through a series of finite element analysis and experiments. In order to minimize the residual vibration during movement, this paper implements input shaping algorithms for the system with the information from the dynamic analysis. The results show that the dynamic performance of the system can be significantly improved by the dynamic analysis and implementation of input shaping

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.314-319
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• 2005

The rubber tire type AGT vehicles had been developed in a few years. And testing are finished on the test track. The extremely differ from heavy train with iron wheels are current collect type and wheel's characteristic. Analysis the current collect gear dynamic with vehicle dynamic and reduce the exchange rate shoes of current collect gear's.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.343-353
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• 1997

This study had been performed to estimate for vibration characteristics of the Power Motor Coaches with Diesel-Hydraulic Drive and to secure a dynamic characteristic construction technology of another rolling stock. Air bags, springs and dampers of Bogie are carefully reviewed in order to improve ride quality. Dynamic analysis had been performed using VAMPIRE program, which had been developed by BRR, and the analysis results had been compared with test data to verify.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.763-764
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• 2006

In this paper, optimized model was designed for the starting characteristic of the Single-Phase Line-Start Permanent Magnet Synchronous Motor by using the Design of Experiment. A field pole angle, thickness and distance from center axis of permanent magnet were selected as design factor. We executed the transient state characteristic analysis of 8 test models. The transient state characteristic analysis was executed by using the 2 dimensional Finite Element Method and the Time Difference Method. We checked the fact that the selected design factor affected starting characteristic of the Line-Start Permanent Magnet Synchronous Motor. Depend on this result we found the optimized design point by using the response optimization.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.350-351
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• 2010

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.1008-1013
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• 2001

KSR-III propulsion system designed in KARI has a gas-pressurization system for propellant feeding system. This system uses a regulator for the control of the ullage pressure of propellant tank and a venturi for passive control of propellant flowrate. This system seems to be very reliable, but the flowrate of propellant varies according to the change of acceleration with the rocket flight. In this paper, dynamic characteristic of KSR-III propulsion feeding system was analyzed in flight condition. The purpose of this research is to find the variation of off ratio and propellant flowrate change for certification condition of engine reliability test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.287-293
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• 2010

본 연구에서는 개방형 로켓엔진시스템의 제어시스템을 구성하기 위한 선행연구로서, 시동특성을 예측하기위해 Simulink 모델을 구성하였다. 구성품별 동특성 모델을 바탕으로 로켓엔진시스템의 예측 프로그램을 구성하였으며, 대상으로 하는 시스템의 천이 작동상태에서의 동특성 변화의 예측과 더불어 그 모델링의 타당성 검증을 위하여 실제 개방형 로켓엔진 상사모델의 수류실험을 통해 실험적으로 측정하여 비교하였다. 또한 Simulink모델이 제어시스템을 구성하기위해 적합한지를 판단하기위해 기 수행된 천이 동특성 예측 프로그램의 결과와 비교하였고 검증하였다.

• Journal of KSNVE
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• v.7 no.6
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• pp.937-943
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• 1997

Viscoelastic materials have the characteristics of elasticity and viscosity. Unlike the metals which show negligible damping characteristics, the damping characteristic of viscoelastic materials like rubber mounts is very important in the analysis of the dynamic system. So there has been a great interest in measuring the damping characteristics of the material can be measured. One is the resonant method which loss factor can be measured only in the resonant frequency. The other is the nonresonant method. In this paper, the test procedure and the physical meaning of the impedance method are introduced. The impedance test results, the loss factor by the impedance method, are compared to the results of the resonant method including some recommendations in the experimental setup.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.565-568
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• 2006

This paper achieved dynamic characteristics with test to use solenoid valve for flight model that have present. Designed pressure control virtual system which PWM solenoid valve to use test result. Examination compared solenoid valve dynamic characteristics in atmosphere and cryogenic fluid and presented technique and valuation method that measured upstream and down stream pressure of solenoid valve, as well as, temperature, excitation voltage etc. These test results could confirm solenoid valve response time and maximum using frequency characteristic at use in atmosphere and cryogenic temperature and this derived design variables pressure control system from those bases.