A study on the FEM modeling method and coupled vibration of main engine-body with torsional vibration of shafting system for marine diesel engine

Under steady state condition, unstable torsional vibration normally does not occur in shafting systems using 4stroke diesel engine due to hysteresis damping of shafting system and relative damping of standard fitted damper. However, the unstable torsional vibration occurs on marine propulsion shafting systems due to slippage of a multi-friction clutch installed between increasing gear box and shaft generator. To identify this unstable vibration and make proper counter measure, the simulation for transient torsional vibration using the Newmark method is introduced in this paper. The mechanism of this unstable vibration is verified by vibration and noise measurements of the shafting system.

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Effect of Coupling Angle of Propeller Blade and Crank of Marine Diesel Engine on First Mode Torsional Vibration (1st Report)

Transactions of the Japan Society of Mechanical Engineers ◽

10.1299/kikai1938.22.506 ◽

1956 ◽

Vol 22 (119) ◽

pp. 506-511

Author(s):

Masuo ANDO

Keyword(s):

Diesel Engine ◽

Torsional Vibration ◽

Marine Diesel Engine ◽

Propeller Blade ◽

Marine Diesel ◽

Coupling Angle

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On the possible increasing of efficiency of ship power plant with the system combined of marine diesel engine, gas turbine and steam turbine, at the main engine - steam turbine mode of cooperation

Polish Maritime Research ◽

10.2478/v10012-008-0010-z ◽

2009 ◽

Vol 16 (1) ◽

pp. 47-52 ◽

Cited By ~ 13

Author(s):

Marek Dzida

Keyword(s):

Diesel Engine ◽

Power Plant ◽

Steam Turbine ◽

Gas Turbine ◽

Combustion Engine ◽

Marine Diesel Engine ◽

Piston Engine ◽

Marine Diesel ◽

Main Engine ◽

Turbine Mode

On the possible increasing of efficiency of ship power plant with the system combined of marine diesel engine, gas turbine and steam turbine, at the main engine - steam turbine mode of cooperation This paper presents a concept of a ship combined high-power system consisted of main piston engine and associated with it: gas power turbine and steam turbine subsystems, which make use of energy contained in exhaust gas from main piston engine. The combined system consisted of a piston combustion engine and an associated with it steam turbine subsystem, was considered. An algorithm and results of calculations of the particular subsystems, i.e. of piston combustion engine and steam turbine, are presented. Assumptions and limitations taken for calculations, as well as comparison of values of some parameters of the system and results of experimental investigations available from the literature sources, are also given. The system's energy optimization was performed from the thermodynamic point of view only. Any technical - economical analyses were not carried out. Numerical calculations were performed for a Wärtsilä slow-speed diesel engine of 52 MW output power.

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Probabilistic Torsional Vibration Analysis of a Marine Diesel Engine Shafting System: The Level Crossing Problem

Journal of Applied Mechanics ◽

10.1115/1.3176196 ◽

1989 ◽

Vol 56 (4) ◽

pp. 953-959 ◽

Cited By ~ 3

Author(s):

Efstratios Nikolaidis ◽

Anastassios N. Perakis ◽

Michael G. Parsons

Keyword(s):

Diesel Engine ◽

Torsional Vibration ◽

Probabilistic Approach ◽

Series Representation ◽

Harmonic Series ◽

Complex Conjugate ◽

Time Interval ◽

Marine Diesel Engine ◽

Level Crossing ◽

Marine Diesel

A probabilistic approach to the torsional vibration problem of a marine diesel engine shafting system has been developed. In this analysis, the shafting shear stress is found to be a Gaussian, harmonizable cyclostationary process with a harmonic series representation consisting of two complex conjugate components. In this paper, the level crossing problem for this stress process is studied. Two methods for estimating the probability that the stress exceeds a specified threshold at least once over a given time interval are presented. In the first method, a local maximum of the process is approximated by the value of the corresponding envelope at the time of occurrence of this maximum. A Markov-type condition is assumed to hold for the local maxima. The second method assumes that the maximum of the process over a reasonable number of cycles is approximately equal to that of the envelope process. The envelope crossings are assumed to constitute a Poisson process. The two methods are applied to estimate the upcrossing probability in various cases. The results of both approaches are found to be in good agreement with those from Monte Carlo simulation.

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