• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권5호
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• pp.245-249
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• 2006

This study tries to test and analyze the static friction torque generated by an electromagnetic clutch. Then the torque is improved by optimizing the shape of armature. For the purpose of design change and optimization of the electromagnetic clutch, the static friction torque prediction is very important. We construct an axi symmetric FEM model for analyzing the static friction torque and used a torque tester for evaluating the real torque. For a test, predicted static friction torque is compared with the experimental one to discuss the rationality of torque analysis process. The analytical result agrees well with experimental data, explaining the validity of the mathematical process and FEM model. After confirming the torque analysis process, the optimization process is investigated. The optimization result shows that the static torque is improved by changing the armature shape.

• 한국생산제조학회지
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• 제24권4호
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• pp.407-413
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• 2015

Research for renewable energy is being performed since it has the merits of little pollution of the environment and sustainable energy resources. Microalgae is attractive as a renewable energy resource. Biomass of the microalgae can be produced by mass culturing, and bulk harvest technology of is needed to produce biomass continuously. Recently, ultrasonic waves were used to harvest the cultivated microalgae continuously. In this study, the separation process using ultrasonic waves was performed to effectively harvest the microalgae. An ultrasonic wave separation resonator was designed and manufactured based on the acoustic field analysis. Separation experiments using design of experiment were carried out, and the influence of experimental variables from the ultrasonic wave separation process was investigated. Mixing conditions of variables were estimated to obtain high separation efficiency and a large microalgae harvest. Experimental results for suitable mixing conditions were compared with simulation results calculated from the state equation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.523-526
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• 1997

Sheanng is one of the most important operating processes in the field of sheet metal manufacturing. Compared with casting, forging and machining, shearing is very economical to obtain the desired shape. In recent years there has been increasing the use of shearing process in the manufacturing of small and light electronic components. In this paper, it has been researched the experimental investigation to examine the mfl uence of shearing process parameters such as clearance and lower holder configuration. Through the experiment results, the more narrow clearance gives the smaller burr height and the removal of lower holder makes the worse sheared surface. And FE simulation of shearing process using DEFORM-2D were camed out and the results compared w~th experimental studies

• Computers and Concrete
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• 제9권3호
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• pp.227-244
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• 2012

A theoretical model for shear strength evaluation of fibrous concrete beams reinforced with stirrups is proposed. The formulation is founded on the theory of plasticity and the stress field concepts, generalizing a known plastic model for calculating the bearing capacity of reinforced concrete beams, to the case of fibrous concrete. The beneficial effect of steel fibres is estimated taking into account the residual tensile strength of fibrous concrete, by modifying an analytical constitutive law which presents a plastic plateau as a post-peak branch. Around fifty results of experimental tests carried out on steel fibrous concrete beams available in the literature were collected, and a comparison of shear strength estimation provided by other semi-empirical models is performed, proving that the numerical values obtained with the proposed model are in very good agreement with the experimental results.

• 소음진동
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• 제9권3호
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• pp.570-576
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• 1999

This paper presents numerical and experimental results of modal parameter identification in a generator stator frame for 500 MW fossil power plants. A commercial finite element analysis S/W was employed for modal analysis. The generator is excited by alternating electromagnetic forces, mainly of 120 Hz in 60 Hz machines, due to magnetic field and electric current in windings. It is necessary to verify that the stator frame has adequate frequency margin from the excitation frequency to avoid possible resonance when operating. Thus, frequency margin required for the stator frame is established using the numerical and experimental results. The results show that the stator frame meets the frequency-margin requirements. Also, results of modal analysis for design modification in order to reduce weights of the stator frame without deteriorating vibration characteristics are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1706-1711
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• 2008

This paper proposes a new Web based-control concept & design method and implementation of LonWorks network system for a large scale renewable energy energy control and monitoring system in building. The Experimental LonWorks network system using LonWorks/Ethernet(Web) server is designed and fabricated. This article addresses issues in architecture of LonWorks/Ethernet sever, embedded processors architecture for converting LonTalks protocol to Modbus protocol and software, and Internet technologies. It is also verified that the multi-induction motor control and monitoring system using LonWorks/Ethernet server have available, interoperable, reliable performance characteristics from the experimental results, Especially, The seamless integration of TCP/IP networks with control networks allows access to any control point from anywhere. Thus, the results provide a available technical data for remote distributed control system of industrial and buildings field.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1763-1771
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• 2004

An experimental investigation was performed to study the characteristics of ER (Electro-Rheological) fluid flow in a horizontal rectangular tube with or without D. C voltage. To determine some characteristics of the ER flow, 2D PIV(Particle Image Velocimetry) technique was employed for velocity measurements. This research found the mean velocity distributions with 0kV /mm, l.0kV /mm and l.5kV /mm for Re=0, 0.62, 1.29 and 2.26. When the strength of the electric field increased, the cluster of ERF was clearly strong along the test tube and the flow rate decreased. The present results will contribute to the economical and compact design of ER fluids system.

• 한국유체기계학회 논문집
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• 제8권2호
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• pp.9-15
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• 2005

This paper presents an experimental and numerical study on the overall performance and local flow characteristics of sirocco fan in a range hood. Measurement of overall performance for sirocco fans were conducted based on AMCA standard 210. The effects of flow blockages due to the motor inside the fan on the fan performance were investigated by experimentally and numerically and the results were compared with each other. The numerical and experimental results show the inlet flow blockage reduces the performance (ie. fan static pressure, design flow rate, maximum efficiency and free delivery flow rate) of fan. It is found that the blockage makes the flow field highly non-uniform through the blade and cause the efficiency decrement.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.196-196
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• 2000

This paper describes a lateral guidance system of an autonomous vehicle, using a neural network model of magneto-resistive sensor and magnetic fields. The model equation was compared with experimental sensing data. We found that the experimental result has a negligible difference from the modeling equation result. We verified that the modeling equation can be used in simulations. As the neural network controller acquires magnetic field values(B$\_$x/, B$\_$y/, B$\_$z/) from the three-axis, the controller outputs a steering angle. The controller uses the back-propagation algorithms of neural network. The learning pattern acquisition was obtained using computer simulation, which is more exact than human driving. The simulation program was developed in order to verify the acquisition of the teaming pattern, teaming itself, and the adequacy of the design controller. The performance of the controller can be verified through simulation. The real autonomous electric vehicle using neural network controller verified good results.

• 전자공학회논문지 IE
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• 제44권1호
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• pp.10-14
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• 2007

InP의 전자와 정공의 이온화계수로부터 추출한 유효이온화계수를 이용하여 InP 다이오드의 항복전압을 위한 해석적 표현식을 유도하였다. 해석적 항복전압 결과를 $N_D=6\times10^{14}cm^{-3}\sim3\times10^{17}cm^{-3}$의 도핑 농도에서 수치적 결과 및 실험 결과와 비교하였다. 각 농도에 따른 해석적 항복전압은 수치 해석적 결과와 매우 잘 일치하였고, 실험 결과와는 10% 이내의 오차로 잘 일치하였다.