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정건화(Kun-Hwa Jung),손정호(Jung-Ho Son),배종국(Jong-Gug Bae) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Marine generator set consists of marine diesel engine and generator and generates electric power in commercial ship and power plant. An excessive vibration in marine generator set causes a malfunction and durability problem of engine and generator. In the initial design stage, the prediction of a global vibration behavior for generator set is very important. In this study, the static and dynamic reduction method based on the Craig-Bampton theory was used to simulate the structural vibration effectively. Full cyclic simulation in time domain was performed and cyclic variation of various dynamic loadings was applied. When the simulation result was compared with the vibration measurement one, it was known that the simulation technique in the design stage is very practical and vibration level of marine generator set meets the international vibration guide.
정건화(Jung Kun-hwa),곽주호(Kwak Ju-ho),김병주(Kim Byung-joo),이종문(Lee Jong-moon) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
Torsional vibration analysis is necessary at design stage to ensure the reliability of a system particularly when the driven machine is a reciprocating compressor. This paper contains the results of torsional vibration analysis and fatigue strength evaluation for 540 ㎾ compressor driving motor. Torsional vibration analysis showed that the 2<SUP>nd</SUP> torsional mode of the entire shaft system has the possibility of resonance with the 14<SUP>th</SUP> order excitation of compressor and twin line frequency of motor at operating speed. Therefore, the analyses were required to ensure the structural reliability of the motor. The fatigue strength was evaluated for the shaft and inner fans using the results of forced vibration analysis. It is concluded that the motor has sufficient fatigue strength under normal operating condition.
정건화(Kun Hwa Jung),강옥현(Oak Hyun Gang),안성찬(Sung Chan An) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10
Drivetrain of the marine medium-speed engine consist of crankshaft, camshaft and gear train system. Since the dynamic characteristic of each drive system is associated with each other, torsional vibration analysis for the whole drivetrain should be considered. In this study, torsional vibration analysis was performed considering the torque excitation forces of crank and cam. Also, the effect of camshaft and gear train on the torsional vibration of the crankshaft was investigated. The analysis result was in a good agreement with the measured data.
정건화(Kun Hwa Jung),이준호(Jun Ho Lee),손정호(Jung Ho Son),류영석(Young Seok Ryoo) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10
The failures of local structure of marine medium-speed diesel engine occurred in durability test. The vibration response of the whole engine was in an acceptance level, but the local structures were broken. ODS test and vibration measurement were carried out in order to investigate the root cause of durability problem. These tests revealed that the root cause of failures was excessive vibration by 4.5th resonance between engine body and local structure. The best solution to reduce the vibration response is to change the type of mount. After a rigid mount was replaced by a flexible mount, maximum vibration level dropped to 72%.
김원현(Won-Hyun Kim),정건화(Kun-Hwa Jung),이수목(Soo-Mok Lee),류영석(Young-Seok Ryoo) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
Diesel power plant(DPP) with the medium speed diesel engine is operated under the very severe condition in aspect of load and operating time as compared with the marine diesel generator set. So, minimized vibration level have to be insured for the more stable operation of engine and generator. The vibration of generator set mainly comes from the resonance between the rigid modes by resilient mount or distortion modes by structural stiffness and the excitation forces of engine. Then, avoidance of resonance with structural modification is generally well known. In this paper, the first order vibration in non-resonance range and local vibration modes were investigated by impact test, response /ODS(operational deflection shape) measurement and 3D finite element analysis for the additional reduction of vibration. The proposed countermeasures were actually applied and their final effects were verified through the in-situ measurement.