• Title/Summary/Keyword: Propulsion Shafting

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A Study on the Coupled Forced Lateral Vibration of Multi-Supported Shafting by the Transfer Matrix Method (전달매트릭스법에 의한 다지점지지계의 연성강제감쇠 횡진동 계산에 관한 연구)

  • 이돈출;박병학;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • v.14 no.2
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    • pp.35-47
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    • 1990
  • The natural frequency of lateral vibration for ship's propulsion shafting tends to become lower as the relative stiffness of supproted system of the propulsion shafting decreases and the weight of shafting increases. Especially, the propulsion shafting of high-power ships such as car ferries, roll-on/roll-off, and container ships are susceptible to lateral vibration for their resonant speeds are happened to be in ordinary operating speed ranges. So far, many papers on the lateral vibration of ship's propulsion shaftings are published but they treated mainly special cases and not explained explicitly the calculation process. In this paper, the calculation processes of undamped and also forced damped lateral vibration by the transfer matrix method are presented and the calculation programs are developed. With the developed computer programs, a ship's propulsion shafting which was introduced on the published paper is analyzed for its lateral vibration and also the lateral vibration of the main drive shaft for a lathe is calculated to show the availiability of developed computer programs.

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Forced Vibration Analysis for Duffing's Vibration Systems with the Multi-Degree-of-Freedom Systems (다자유도계를 갖는 듀핑 진동계의 강제진동해석)

  • 전진영;박용남;김정렬;김의간
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.18-24
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    • 2000
  • As ship's propulsion shafting system has been complicated, many linear methods that have been used until now are not sufficient enough to produce proper solutions and these solutions are ofter unreasonable. So we need to solve nonlinear systems, and many methods for solving nonlinear vibration system have been developed. In this study, the propulsion shafting system was modeled with Duffing's nonlinear vibration system and multi-degree-of-freedom, and analyzed by using Quasi-Newton method. And for the purpose of confirming the reliability of the calculating results for nonlinear forced torsional vibration of the propulsion shafting system, the nonlinear calculated results were compared with the linear calculated ones for ship's propulsion shafting system. In the result, for analysis of the forced torsional vibration of the propulsion systems with nonlinear elements, the modified Newton's method is confirmed reasonable.

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A study on the calculation of forced torsional vibration with damping for the marine diesel engine shafting by the mechanical impedance method (기계적 임피던스법에 의한 박용 디젤기관 추진축계의 강제감쇠 비틀림 진동의 계산에 관한 연구)

  • 김정열;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • v.9 no.4
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    • pp.307-316
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    • 1985
  • Nowadays, the natural frequencies and their relative amplitudes of torsional vibration for the marine diesel engine shafting are usually calculated by the Holzer method and also its resonant amplitudes are estimated by the energy method, that is, by equating the exciting energy to the damping one. Therefore, the forced vibration amplitudes out of the resonant points can not be calculated by the above-mentioned method. And so, the reasonable barred-ranges of torsional vibration can not be set and also the flank of resonant point which locates near the calculation limit can not be estimated. For such problems, the equation of forced vibration with damping must be solved directly and these results can be utilized to derive the synthesized torsional vibration of the marine diesel engine propulsion shafting. In this study, the equation of forced vibration with damping for the marine diesel engine propulsion shafting is derived and its steady-state vibration is calculated by the mechanical impedance method. For numerical calculation of the actual propulsion shafting a computer program is developed. In order to prove the reliability of this program, an actual ship's propulsion shafting whose torsional vibration was measured is analyzed and the calculated propulsion shafting whose torsional vibration was measured is analyzed and the calculated results are compared with the measured ones. And also, they are compared with the calculated results which were obtained by the modal analysis.

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Optimum Design of Diameters of Marine Propulsion Shafting by Binary-Coded Genetic Algorithm and Modal Analysis Method (이진코딩 유전알고리즘과 모드해석법을 이용한 선박 추진축계의 직경 최적설계)

  • Choi, Myung-Soo;Moon, Deok-Hong;Seol, Jong-Ku
    • Journal of Power System Engineering
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    • v.7 no.3
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    • pp.29-34
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    • 2003
  • Genetic algorithm is a optimization technique based on the mechanics of natural selection and natural genetics. Global optimum solution can be obtained efficiently by operations of reproduction, crossover and mutation in genetic algorithm. The authors developed a computer program which can optimize marine propulsion shafting by using binary-coded genetic algorithm and modal analysis method. In order to confirm the effectiveness of the developed computer program, we apply the program to a optimum design problem which is to obtain optimum diameters of intermediate shaft and propeller shaft in marine propulsion shafting. Objective function is to minimize total mass of shafts and constraints are that torsional vibration stresses of shafts in marine propulsion shafting can not exceed the permissible torsional vibration stresses of the ship classification society. The computational results by the program were compared with those of conventional design technique.

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Excitation Response Estimation of Polar Class Vessel Propulsion Shafting System

  • Barro, Ronald D.;Lee, Don-Chool
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.463-468
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    • 2011
  • The prospect of Arctic trade transportation opening on a year-round basis creates a vast opportunity of exploring untapped resources and shortened navigational routes. However, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. Further, classification societies recognize the need to upgrade the Unified Rules concerning elements to meet current Polar requirements. Hence in this paper, excitation torque calculation on Polar class vessels propulsion shafting system will be reviewed. The propeller - ice interaction load effect, which is a main consideration of excitation source of Polar Class propulsion shafting system, on shaft design calculation will be analyzed.

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Design of Propulsion Shafting System for Controllable Pitch Propeller (I : Latout Design with Sizing) (가변추진기 추진축계시스템의 설계 (제 I 보 : 외형설계 ))

  • 김기인;전효중;박명규;김정렬
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.129-134
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    • 2002
  • This study is focused on the layout design with sizing for the main propulsion shafting with controllable pitch propeller system. For appropriate design and successful manufacturing of controllable pitch Propeller system, it is based on specifications to be required from the customer as well as the stresses calculation and analysis of main propulsion system for hollow shafting. And it must be performed according to the U.S military specifications MIL-STD-2189(SH) with drawing of NAVSHIPS 803-2145807, and also the stress analysis by applying safety factor. The results are as follows : 1. For the main propulsion system with controllable pitch propeller, it is designed the following items propeller diameter, hub diameter, dimensions of oil distribution or actuating unit based on shaft mounting type, diameters of propeller and intermediate shaft, dimension of split muff coupling, coupling flange thickness and of coupling bolt diameter. 2. As the results, we can get complete our own design ability for the main propulsion shafting with controllable pitch propeller system with critical data which are necessary to establish shafting arrangement from the ship building companies.

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A Study on the 2-node Torsional Vibration for Marine Diesel Engine Crankshaft (선박용 디젤기관 크랭크 축계의 2절 비틀림 진동에 대한 연구)

  • Choi, Moon-Keel;Park, Kun-Woo
    • Special Issue of the Society of Naval Architects of Korea
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    • 2008.09a
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    • pp.54-61
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    • 2008
  • With the development of computer program in calculation for torsional vibration of ship's propulsion shafting it has become possible to calculate all order's vibratory amplitude, vibratory torque, vibratory stress and synthesis value at all concerned revolutions by way of solving the vibratory equation directly. Though this kind of propulsion shafting vibration calculation method makes it possible to get generalized and precise result of calculation, the unexpected critical crankshaft torsional vibration has still appeared in maneuvering range of the engine. A close investigation has been carried out to find out the cause for the 2-node propulsion shafting torsional vibration of the crankshaft that exceeded the limitation value near the MCR 104rpm on the sea trial of the recently delivered 6000TEU class container vessel from HHIC. In conclusion, as the latest super-output engine with heavy crankshaft and propeller mass seems to be liable to 2-node torsional vibration of crankshaft, it is recommend that, in the design stage of propulsion shafting, its torsional vibration condition must be more carefully checked.

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A Study on the Analysis of Lateral Vibration of Flexible Shafting System for Propulsion and Lift in Air Cushion Vehicle (공기부양선의 추진 및 부양축계 횡진동 해석에 관한 연구)

  • Son, Seon-Tae;Kil, Byung-Lea;Cho, Kwon-Hae;Kim, Jung-Ryul
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.2
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    • pp.241-249
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    • 2008
  • In this study, lateral vibration analysis has been conducted on a propulsion and lift shafting system for an air cushion vehicle using ANSYS code. The shafting system is totally flexible multi-elements system including air propeller, aluminum alloy of lift fan and thin walled shaft with flexible coupling. The analysis included the lateral natural frequencies, mode shapes and harmonic analysis of the shafting system taking into account three-dimensional models for propulsion and lifting shaft system. In case of ACV the yawing and pitching rate of craft will be quite high. During yawing and pitching of craft significant gyroscopic moment will be applied to the shafting and will generate high amplitude of lateral vibration. So, such a shafting system has very intricate lateral vibrating characteristics and natural frequencies of shafting must be avoided in the range of operating revolution. The control of lateral vibration is included in this study.

Unstable Torsional Vibration on the Propulsion Shafting System with Diesel Engine Driven Generator (디젤엔진 구동 발전기를 갖는 추진축계의 불안정한 비틀림진동)

  • 이돈출
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.936-942
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    • 1999
  • Unstable torsional vibration on the marine ship's propulsion shafting system with diesel engine occurred due to a slippage of multi-friction clutch which was installed between increasing gear and shaft generator. In this paper, the mechanism of this vibration was verified via torsional, whirling, axial and structural vibration measurements of shafting system and noise measurement of gear box. And it was also identified by the theoretical analysis method.

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Dynamic Characteristics of torsion for Marine Propulsion Shafting system with Elastic Rubber Coupling (고무 탄성커플링을 갖는 선박 추진용 축계 비틀림의 동특성)

  • 이돈출;김상환;유정대
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.742-748
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    • 2003
  • As for marine propulsion shafting system using 4 stroke diesel engine, it is common to apply reduction gear box between diesel engine and shafting with a view of increasing mechanical efficiency, which inevitably require elastic coupling due to avoid chattering and hammering inside of gear box. In this study, optimum method of rectifying propulsion shafting system in case of 750ton fishing vessel specially in a view of torsional vibration, is theoretically studied. After exchange of diesel engine and gear box, analysis result of torsional vibration get worse and so some countermeasure are needed. The elastic coupling is modified from present block type rubber coupling showing relatively high torsional stiffness to rubber coupling with two series elements directly connected. The vibration measurement using two laser torsion meters was done during sea trial, whose results are compared to those of calculation and verified.

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