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

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

Transient and Unstable Torsional Vibrations on a 4-Stroke Marine Diesel Engine

2003 ◽  
Author(s):  
D. C. Lee ◽  
J. D. Yu
Keyword(s):  
Diesel Engine ◽  
Torsional Vibration ◽  
Marine Diesel Engine ◽  
Torsional Vibrations ◽  
Steady State Condition ◽  
Marine Propulsion ◽  
Friction Clutch ◽  
Marine Diesel ◽  
Noise Measurements ◽  
Unstable Vibration

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.

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

1989 ◽  
Vol 56 (4) ◽  
pp. 953-959 ◽  
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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