한국해양대학교

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크랭크스로우의 單面變化를 통한 多氣筒 2行程 디젤機關의 2節 비틀림振動 制御

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dc.contributor.author 황상재 -
dc.date.accessioned 2017-02-22T07:10:25Z -
dc.date.available 2017-02-22T07:10:25Z -
dc.date.issued 2009 -
dc.date.submitted 56905-02-20 -
dc.identifier.uri http://kmou.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002176051 ko_KR
dc.identifier.uri http://repository.kmou.ac.kr/handle/2014.oak/10385 -
dc.description.abstract Recently a marine engine has been needed a large scale to have higher power since vessels are needed to be bigger size to transfer more baggage quickly. According to this need, the marine engine has required more cylinders and bigger bore. Therefore present time, shafting system suffers from 2 node vibration that has never occurred before for the marine engines which are below 7 cylinders. 2 node vibration occur in a crankshaft and a propeller shaft. It is different with 1 node vibration which normally occur in intermediate shaft of the propulsion shafting system. The crankshaft can be mainly damaged only since the crankshaft is weaker in torsional vibration than propeller shaft so the limit of IACS is stricter for crankshaft. Generally a solution of the problem by 2 node vibration is what a vibration damper is applied. However, if the engine has a higher power then now engine, the size of damper will be bigger to have high damping coefficient so it will be able to affect to a bearing with heavy weight. Also the cost is high to buy and to install and the time limit for delivery is needed almost an year from a decision to delivery. By reason of these, engine maker should try to find other solutions to solve problem of 2 node vibration without the vibration damper. According to these reasons, the other solution was reviewed on this paper. That is the method to reduce the torsional stress in a crankshaft by increasing a diameter of journal and pins synchronously at the position where the maximum torsional stress is occurred. The maximum torsional stress can be occurred at a node but according to excitation characteristics, it can be occurred the other position. Because the position of the maximum torsional stress can be changed occasionally, so the characteristics have to be confirmed. The node position should be defined since the node surely can affect to the crankshaft with high vibration and if there are some mistakes with choosing the position to increase the diameter of journal and pins, the maximum torsional stress can be increased. This study is explained for two cases. One of those is the case of what the node position is different with the maximum torsional stress and the other one is what the node position and the maximum torsional stress position are the same. For two cases, the first case is needed to apply a tuning wheel to change the position of node to have same position with the maximum torsional stress position since it is effective and easy to control 2 node vibration but in case of 12K98MC-C, the initial maximum torsional stress is too high in the crankshaft and several cranks have similar level to the maximum torsional stress. Owing to such a property, it is not able to control with only increasing the diameter of journal and pins. It should need a torsional vibration damper to reduce. For the second case, two adapted shafting systems are all controlled with increasing the diameter and changing the mass inertia of moment of flywheel. The effect of proposed method has been confirmed through this study and it will be able to be applied with a vibration damper if the engine which has much higher power is developed. For the future plan, the exact position of the node should be defined through FEM to increase only a diameter of a journal or a pin and before adopting this method, it has to be confirmed the validity of manufacture at design stage and characteristics of engine structural vibration with increasing diameter of crank, etc. -
dc.description.tableofcontents 제1장 서론 = 1 1.1 연구 배경 = 1 1.2 연구 목적 = 3 제2장 비틀림진동의 제어 방안 = 5 2.1 추진축계의 고유진동수 변경 = 6 2.2 기진력 제어 = 8 2.3 비틀림진동 댐퍼 설치 = 10 2.4 부가응력 저감 = 14 제3장 크랭크스로우의 강성계수와 질량 관성모멘트 = 15 3.1 크랭크스로우의 강성계수 = 16 3.2 크랭크스로우의 질량 관성모멘트 = 21 제4장 실선 크랭크스로우의 축경 변경이 2절 비틀림진동에 미치는 영향 = 22 4.1 크랭크스로우의 축경 변경에 따른 8K80MC-C 엔진 축계의 2절 비틀림진동 제어 = 24 4.2 8S70MC-C 엔진 축계의 크랭크축 비틀림 부가응력 제어 = 34 4.3 8K90MC-C 엔진 축계의 크랭크축 비틀림 부가응력 제어 = 37 4.4 12K98MC-C 엔진 축계의 크랭크축 비틀림 부가응력 제어 = 42 제5장 결론 = 48 참고문헌 = 50 -
dc.language kor -
dc.publisher 한국해양대학교 대학원 -
dc.title 크랭크스로우의 單面變化를 통한 多氣筒 2行程 디젤機關의 2節 비틀림振動 制御 -
dc.title.alternative Two node torsional vibration control of the multi-cylinder two stroke diesel engine with changing section area of crank throw -
dc.type Thesis -
dc.date.awarded 2009-02 -
dc.contributor.alternativeName Hwang -
dc.contributor.alternativeName Sang-Jae -
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기계공학과 > Thesis
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