• 소음진동
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• 제9권3호
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• pp.554-564
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• 1999

This paper presents the analytical method to evaluate the seismic responses on steam turbine-generator rotor system. Deterministic analytical methods, such as response spectrum approach, modal superposition method and direct integration method, are used to calculate the seismic response. The computer software is also developed based on the methods then can be applied to estimate the seismic safety of turbine-generator rotor system for power plants. Numerical example of a steam turbine-generator rotor system of 1007MW nuclear power plant is presented. The aseismatic performance are checked by comparing maximum seismic deflection at bearing positions with bearing clearance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1034-1039
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• 2000

In turbo-machines operated at high speeds through gear speed increasers a precise coupled analysis of lateral and torsional vibrations is required to achieve highly reliable designs with low vibration and low noise levels, where the vibration coupling is due to the gear pair mesh stiffness. In this paper, applying the generalized coupled lateral-torsional finite element model of a gear pair element, has been analyzed a coupled lateral-torsional vibration of the prototype 800 RT turbo-chiller rotor-bearing system with a bull-pinion gear speed increaser. Results have shown that the coupled torsional natural frequencies have decreased due to the coupling effect of lateral vibration and particularly, the 2nd torsional natural frequency and its mode shape have had big changes. However, changes of lateral vibration characteristics have been noticed only at high lateral whirl natural frequencies above 15,000 rpm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.220-226
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• 2002

A general solution method is presented to obtain the unbalance response orbit from the finite element based equations of motion of a gear-coupled two-shaft rotor-bearing system. Particularly, are proposed the analytical solutions of major and minor axis radii of the orbit. The method has been applied to analyze the unbalance response of a 800 refrigeration-ton turbo-chiller rotor-bearing system, having a bull-pinion speed increasing gear. The bumps of unbalance responses have been observed at the first torsional natural frequency due to the coupling of lateral and torsional dynamics by the gear meshing. Further, the proposed analytical solutions have been validated with results obtained by a full numerical approach.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.625-630
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• 2007

This paper accounts for derivations and formulations of the finite element dynamic equation of the rotor-bearing system to analyze its whirling speed. It turns out to be a different form from previous researcher's because of different successive sequences of Euler angles. Correspondingly the adoption of other rotation tensor will be needed for a consistent derivation of the dynamic equation. The process of its finite element formulation with consistent mass matrix and gyroscopic matrix involves a general definition of the modal analysis or the Eigen analysis for the damped system in the inertial frame and rotating frame, respectively.

• 기계와재료
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• 제21권2호
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• pp.50-73
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• 2009

본 고는 중대형 풍력터빈의 핵심부품인 로터 블레이드, 대형베어링, 증속기, 발전기, 전략변환장치, 타워 등에 사용되는 주요재료에 대한 설명과 제조방법 및 평가 방법 등에 대해 다루어 졌다. 일반적으로 풍력터빈을 구성하는 소재는 금속소재와 비금속재료로 구분되며, 비금속재료는 대부분 복합재료로써 풍력 블레이드에 적용되고 있다. 현재 육상용 풍력터빈의 한계를 극복하기 위한 대안으로, 해상용 풍력터빈에 대한 관심이 집중되고 있으며, 이러한 극지 해상의 대형 시스템에 활용되고 있는 금속소재의 경우, 고강도, 저온인성, 내피로, 내식성 등이 우수한 강재를 요구하기에 이르렀다. 이에 따라, 여러 소재 측면의 요구를 충족하기 위한 소재설계의 비중이 점차 고조되고 있으며, 이러한 시점에 본 고를 통해 풍력터빈에 활용되고 있는 소재의 전반적인 내용과 관련 소재부품의 제조 및 평가 방법등의 이해를 돕고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.605-611
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• 2000

Presented in this paper is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is not only possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speeds but also the damping ratio and eccentricity of the system can be identified at the same time. Two types of test rotors were tested on the Rotor Dynamics Test Facility at the Rotordynamics Lab., KIMM, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends of direction of subtle changes in the dynamic characteristic parameters over a long periods of time.

• 한국정밀공학회지
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• 제25권10호
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• pp.99-106
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• 2008

5kWh FESS(Flywheel Energy Storage System) using AMB(Active Magnetic Bearing) has been under development and 1st trial system has been finished and run the operating test. Unfortunately, the test result was not satisfactory because FESS could increase the rotational speed up to 9,000 rpm only although the target rotational speed is 18,000rpm. It's because 1st bending mode frequency of flywheel shaft was too low and imbalance response was too big. To achieve the target speed, 1st bending mode and imbalance response must be improved and the whole FESS needed to be designed again. This paper presents the newly designed FESS and what has been changed from the 1st trial FESS to improve 1st bending mode and imbalance response. The experimental results to see how much 1st bending mode frequency was improved are presented, too.

• Journal of Advanced Marine Engineering and Technology
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• 제34권8호
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• pp.1057-1067
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• 2010

다단 기어연쇄, 베어링, 축, 로터로 구성되는 함포용 synchro system의 구동장치를 개발하기 위하여, AGMA규격에 의한 기어 굽힘강도, 면압강도해석, 기어치형설계를 포함한 정적설계를 수행하였다. 또한 전달행렬법을 효과적으로 적용시킬 수 있는 Hibner's branch법과 자유도가 큰 경우에도 계산 오차 없이 고유특성치를 빠뜨리지 않고 산출할 수 있는 ${\lambda}$-matrix법을 도입하여 함포용 Synchro system의 좌우 선회용과 상하 고각형의 위험속도 해석 및 평가를 하였고, 운전속도 범위 내에 위험속도가 존재하지 않았다.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1661-1672
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• 2000

An immune system has powerful abilities such as memory, recognition and learning how to respond to invading antigens, and has been applied to many engineering algorithms in recent year. In this pap er, the combined optimization algorithm (Immune- Genetic Algorithm: IGA) is proposed for multi-optimization problems by introducing the capability of the immune system that controls the proliferation of clones to the genetic algorithm. The optimizing ability of the proposed combined algorithm is identified by comparing the result of optimization with simple genetic algorithm for two dimensional multi-peak function which have many local optimums. Also the new combined algorithm is applied to minimize the total weight of the shaft and the transmitted forces at the bearings. The inner diameter oil the shaft and the bearing stiffness are chosen as the design variables. The dynamic characteristics are determined by applying the generalized FEM. The results show that the combined algorithm and reduce both the weight of the shaft and the transmitted forces at the bearing with dynamic conatriants.

• 한국소음진동공학회논문집
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• 제14권8호
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• pp.684-694
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• 2004

Presented in this dissertation is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speed of the system. In the course of the procedures illustrated, not only the critical speed but also the damping ratio and the eccentricity of the system can be identified at the same time. Test rotor was tested on the Rotor Dynamics Test Facility at the Korea Institute of Machinery ＆ Materials. Korea, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends or direction of subtle changes in the dynamic characteristic parameters over a long periods of time.