• International Journal of Control, Automation, and Systems
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• 제3권spc2호
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• pp.262-269
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• 2005

In this paper, a nonlinear robust control approach is applied to design a controller for the Static Synchronous Compensator (STATCOM). A robust control dynamic model of STATCOM in a one-machine, infinite-bus system is established with consideration of the torque disturbance acting on the rotating shaft of the generator set and the disturbance to the output voltage of STATCOM. A novel recursive approach is utilized to construct the energy storage function of the system such that the solution to the disturbance attenuation control problem is acquired, which avoids the difficulty involved in solving the Hamilton-Jacobi-Issacs (HJI) inequality. Sequentially, the nonlinear disturbance attenuation control strategy of STATCOM is obtained. Simulation results demonstrate that STATCOM with the proposed controller can more effectively improve the voltage stability, damp the oscillation, and enhance the transient stability of power systems compared to the conventional PI+PSS controller.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.17-28
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• 1992

During the last decade, engine makers have developed new types or increasing power rate engines to enlarge theirs marketing shear in two stroke, low-speed diesel engines. As the results, these engines have increased the additional stresses due to torsional vibration more than old model engines. The torsional vibration dampers are necessary in order to reduce heigher additional stresses of intermediate and crank shaft in these engine. In this paper, the optimum designing of Geislinger type torsional Damper has been carried out, based on the theoretical conception. The dynamic characteristics and performance fo dampers are estimated by the measuring results obtained with the monitoring system of dampers and additional stresses of propulsion shafts.

• 대한기계학회논문집B
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• 제33권12호
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• pp.933-938
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• 2009

Hot test of a full-scale turbopump for a 30-ton-thrust liquid rocket engine was carried out. The turbopump is composed of an oxidizer pump, a fuel pump, and a turbine on a single shaft. Model fluid was used in the test, that is, hot air for the turbine and water for the pumps. The turbopump was operated stably at full speed for 120 seconds. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test are compared with those from the turbopump component tests which were performed at about half of the design rotational speed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.547-550
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• 1997

The dynamic behavior of rotor-bearing system has been investigated using finite element method. A procedure is presented for dynamic modeling of rotor-bearing system which consist of shaft elements, rigid disk, flexible bearing and support structures. A finite element model including the effects of rotary inertia, shear deformation, gyroscopic moments is developed. Linear stiffness and damping coefficient are calculated for 3 lobe sleeve bearing. The whirl frequency, mode shape, stability and unbalance response of rotor system included effect of bearing coefficient and support structures are calculated.

• 한국정밀공학회지
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• 제20권9호
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• pp.118-125
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• 2003

In this study, we carried out the finite element analysis for the screw of centrifuge that is the weakest part of the centrifuge for sewage management. Centrifugal force caused by rotation with velocity of 4000rpm was applied at the screw. Structural analysis was done with respect to the change of the ratio of blade pitch($R_P$), shaft diameter($R_D$) and extended hole($R_E$). When the area of circular hole is equal to that of extended holes, maximum equivalent stresses in the screw with circular and extended circular hole were compared. And then natural frequency analysis was executed for the same model. Three mode shapes were used to explain the vibration characteristics of each screw. Convergence study was accomplished fur more accurate results.

• 한국정밀공학회지
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• 제8권4호
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• pp.137-145
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• 1991

A universal joint is a connecting device of two hinges which can transmit torque from one shaft to another at fixed or at varying angles of intersection. It has been used properly not only as rotational but also as intermittent motion. For the particular kinematics condition of a universal joint, torsional and bending vibrations are produced excessively in an elastic driveline. In this paper only the torsional vibration behavior of a driveline with universal joints is analyzed numerically with the discrete model and a design method of the dynamic vibration damper is proposed, in order to reduce torsional vibrations especially in resonance region as a result of parametric variation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.312-318
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• 2001

This paper suggests the finite element method to analyze the dynamic characteristics of a rotating HDD system including the supporting structure with general shape. The flexible supporting structure was modeled by tetrahedra elements to produce a finite element model of disk-spindle-shaft-housing system and the dynamic characteristics of the HDD system was investigated due to the change of rotating speed. The validity of the presented method was verified by the modal testing. The supporting structure has an crucial effect on lower modes for HDD system, so that it is required to consider the supporting structure to accurately analyze the dynamic characteristics of HDD system.

• 소음진동
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• 제8권4호
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• pp.670-682
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• 1998

Ball type automatic balancer is used to reduce the vibration caused by unbalance of rotor. In this study, A analytic modeling of a front loaded washing machine with ball type automatic balancer has been suggested theoretically and ADAMS has been used to analyze the dynamic characteristics of automatic balancer. It is found from simulation and experimental results that the automatic balancer suppress the steady state vibration of washing machine effectively. The test results match with the simulation results of ADAMS, thereby the dynamic model of ADAMS can be used as virtual prototype to predict the vibration characteristics which could be changed by the modification of design variableand can reduce the design cycle sharphy. To maximize the balancing effect of automatic balancer, the friction between balls and race and the deviation between geometric center and rotation center of drum need to be minimized and the optimum design for the stiffness of flange shaft and the angular acceleration of drum should be achieved.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.334-339
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• 2000

In order to predict the noise of the spur gear system, a simplified model of spur system including the housing is studied. The spur gear is modeled as a single degree of freedom system. The shaft-housing system is modeled as a clamped circular plate connected with a beam. The moment components of the beam excited by the spur gear mesh force are considered in the calculation of plate vibration and radiated noise. The out-of-displacements of the clamped circular plate due to the r-direction moment and ${\theta}$-direction moment are calculated. Radiated noise from the plate in the air is also calculated using Rayleigh integral. Using the numerical example, the numerical validation of the analytical procedure on the noise prediction are given.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1119-1126
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• 2000

This paper is concerned with the design and application of an Electro-Rheological(ER) fluid damper to suppress the vibration of a rotor system. The system is flexible with a slender shaft and a thin disk, being supported by two ball bearings. In addition, to investigate the system performances also in the high speed range, the driving torque is made transmit through a speed increasing gear train. Along with the experiments, to predict and compare the ER damper effect, the rotor system is simulated as to its free and forced vibration characteristics by means of a finite element method code, which is assembled with the mathematical model of the designed ER damper.