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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korea Society For Power System Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Power System Engineering
Editor in Chief :
Volume & Issues
Volume 5, Issue 4 - Nov 2001
Volume 5, Issue 3 - Aug 2001
Volume 5, Issue 2 - May 2001
Volume 5, Issue 1 - Feb 2001
Selecting the target year
Trends of Research and Development for LNG Cold
Yun, Jeong-In ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 5~10
Analysis of Temperature Distribution using Finite Element Method for SCS Insulator Wafers
Kim, O.S. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 11~17
Micronization of sensor is a trend of the silicon sensor development with regard to a piezoresistive silicon pressure sensor, the size of the pressure sensor diaphragm have become smaller year by year, and a microaccelerometer with a size less than
has been realized, In this paper, we study some of the bonding processes of SCS(single crystal silicon) insulator wafer for the microaccelerometer. and their subsequent processes which might affect thermal loads. The finite element method(FEM) has been a standard numerical modeling technique extensively utilized in micro structural engineering discipline for design of SCS insulator wafers. Successful temperature distribution analysis and design of the SCS insulator wafers based on the tunneling current concept using microaccelerometer depend on the knowledge about normal mechanical properties of the SCS and
layer and their control through manufacturing processes.
Effects of Heat Transfer on Geometries of Spirally Corrugated Tubes in Annuli
Ahn, Soo-Whan ; Oh, Se-Kyung ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 18~23
This paper is to present the results of a comprehensive study on heat transfer in annuli with spirally corrugated inner tubes in the turbulent regime. Tube surface-temperature measurements were used to explain the enhancement phenomena in the annuli with several different corrugated tubes. Nusselt numbers were between 1.1 and 2 times the smooth annulus values. These enhancement values can be used to determine the appropriate range of applicability for spirally corrugated annuli.
Vibration Analysis of Structures Using the Transfer Stiffness Coefficient Method and the Substructure Synthesis Method
Choi, Myung-Soo ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 24~30
The substructure synthesis method(SSM) is developed for overcoming disadvantages of the Finite Element Method(FEM). The concept of the SSM is as follows. After dividing a whole structure into several substructures, every substructures are analyzed by the FEM or experiment. The whole structure is analyzed by using connecting condition and the results of substructures. The concept of the transfer stiffness coefficient method(TSCM) is based on the transfer of the nodal stiffness coefficients which are related to force vectors and displacement vectors at each node of analytical mode1. The superiority of the TSCM to the FEM in the computation accuracy, cost and convenience was confirmed by the numerical computation results. In this paper, the author suggests an efficient vibration analysis method of structures by using the TSCM and the SSM. The trust and the validity of the present method is demonstrated through the numerical results for computation models.
Attenuation of Pressure Fluctuations in Oil Hydraulic Pipeline with Bellows Type Accumulator
Lee, I.Y. ; Jung, Y.G. ; Lee, S.J. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 31~37
Pressure propagation and attenuation characteristics in a hydraulic pipeline with a bellows type accumulator was investigated by theoretical analyses and experiments. In the first stage of the study, equations to evaluate the amount of oil volume charged into the bellows together with nitrogen gas were proposed. In the next stage, the authors suggested a mathematical model based on transfer matrix method to describe the dynamic characteristics of the pipe element with a metal bellows type accumulator. Through comparisons and considerations of the experimental and the numerical data shown in frequency domain, the validity of the mathematical model was confirmed.
Dynamic Characteristics of Bolted Joint in Tube Line by External Vibration
Park, T.W. ; Kim, Y.K. ; Shin, G.S. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 38~43
This paper describes the effect of dynamic characteristics in tube line by external vibration conveying fluid with the power steering system. By the experimental analysis we found out that the factor of system vibration is the fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through experiment. Experiments are modal test, frequency response function in continuous system, and vibrating tests when the system is driving with bolted clamping joint condition. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than the wave induced vibrations. And we found that the tendency of system vibration level was decreased by bolting force, bolting condition and clamping distance.
A Study on Modeling and Identification for the Magnetic Bearing System
Shim, S.H. ; Kim, C.H. ; Yang, J.H. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 44~52
This paper considers a modeling and identification for the MIMO magnetic bearing system. To obtain the nominal plant transfer functions, we have experimented on the frequency response by a closed-loop identification method because the system is unstable essentially. We suggest a method of curve-fitting for obtaining the transfer function from the frequency responses by using the system's modeling structure and two controllers which are different from each other. From the frequency response results, we found the effects of coupling by opposing controllers. And using this effects and the system's modeling structure, we could obtain the transfer functions of which have the same modularized denominators.
A Study on Modeling for the Magnetic Bearing System by Numerical Analysis
Shim, S.H. ; Choi, M.S. ; Kim, C.H. ; Moon, D.H. ; Yang, J.H. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 53~60
This paper considers a modeling for the MIMO magnetic bearing system. The rotor is flexible and has a complex shape. To obtain the nominal plant transfer functions, we perform a numerical analysis by using the finite element method(F.E.M.) for the rotor's dynamics, and make a nominal model by reducing the modes from the results. And, we have experimented on the frequency response by a closed-loop identification method, and compared it with the simulation's result on the closed-loop control system.
Durability Estimation for ER(Electro-Rheological) Fluids of Arabic Gum Components
Kim, O.S. ; Park, W.C. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 61~66
Electro-Rheological(ER) fluids undergo a phase-change when subjected to an external electric field, and this phase-change typically manifests itself as a many-order-of magnitude change in the rheological behavior. This paper presents experimental results on material properties for an ER fluids of arabic gum components subjected to electrical fatigues. As a first step, ER fluids are made of arabic gum 25% of particle weight-concentration. Following the construction of test mechanism for estimated durability of ER fluid, the dynamic yield stress, shear stress and current density of the ER fluids are experimentally distilled as a function of DC electric field. The durability estimation of operated ER fluids are distilled and compared with those of unused ER fluids. In addition, the surface roughness of the employed electrode for copper and aluminum are evaluated as a function of the number of the electric-field cycles.
The effect of compress residual stresses of shot peening for fatigue strength of SUP7 and SAE9254 steel
Park, K.D. ; Jung, C.G. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 67~73
Recently the steel parts used at automobiles are required to be used under high stress more than ever before in need of the weight down. To achieve this requirement of a high strength steel, it must be necessary to decrease inclusion content and surface defect as like decarburization, surface roughness etc.. In this study, the surface conditions are measured to know the influence on fatigue properties by two cases of two-stage shot peening iud single-stage shot peening for two kinds of spring steel(SUP7, SAE9254). This study shows the outstanding improvement of fatigue properties at the case of two-stage shot peening in the rotary bending fatigue test and this is assumed to be from decreasing the surface roughness unchanging the surface hardness increasing the compressive residual stress. Results also show fatigue failures originated at inclusion near surface, and this inclusion type is turned out to be a alumina of high hardness.
Fabrication and Mechanical Properties of
Composites by Pressureless Infiltration Technique
Jin, H.G. ; Oh, M.S. ; Kim, Y.S. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 74~81
The infiltration behavior of molten Al-alloy, microstructures, hardness, and the interfacial reactions of
composites fabricated by the pressureless infiltration technique were investigated. It was made clear that both the weight fraction of SiC reinforcement and additive Mg content considerably influenced on the infiltration behavior of the molten Al-alloy matrix. Complete infiltration of molten Al-alloy achieved under the conditions that weight fraction of SiC content is more than 30wt%, and additive Mg content is more than 9wt%. Interfacial region of Al-alloy matrix and SiC reinforcement phase,
was formed by the reaction between Mg and SiC. Another reaction product AlN was also formed by the reaction between Al-alloy matrix and gas atmosphere nitrogen.
A Study on the Static Sensitivity Analysis Algorithm Using the Transfer of Stiffness Coefficient
Choi, Myung-Soo ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 82~89
To design a structural or a mechanical system with the best performance, the main procedure of a typical design usually consists of repeated modifications of design parameters and the investigation of the system response for each set of these parameters. But this procedure requires much time, effort and experience. Sensitivity analysis can provide systematic information for improving performance of a system. The author has studied on the development of the structural analysis algorithm and suggested recently the transfer stiffness coefficient method(TSCM). This method is very suitable algorithm to a personal computer because the concept of the TSCM is based on the transfer of the nodal stiffness coefficients which are related to force and displacement vectors at each node. In this paper, a new sensitivity analysis algorithm using the concept of the TSCM is formulated for the computation of state variable sensitivity in static problems. The trust of the proposed algorithm is confirmed through the comparison with the computation results using existent sensitivity analysis algorithm and reanalysis for computation models.
A Study on the Pressure Control of a Pneumatic Pressure Vessel Considering Dynamic Characteristics of Pneumatic Transmission Line
Jang, J.S. ;
Journal of the Korea Society For Power System Engineering, volume 5, issue 4, 2001, Pages 90~96
In this study, a robust controller to control pressure in a pneumatic pressure vessel considering dynamic characteristics of pneumatic transmission line is proposed. Dynamic characteristics of transmission line using compressible fluid is changed by the flowing states of the fluid. So, if the fixed gain controller is designed based on a fixed model, the performance of the control system could be destabilized or degraded. The controller designed in this study is composed of two parts. The one is to reject modelling error based on the disturbance observer, the other is to obtain the control performance. The control results with the designed controller show that the robustness of the control system is achieved regardless of the change of the model of the transmission line. Therefore, the designed controller can be utilized for the performance improvement of the pressure control system using compressible fluid such as air and gas