Modelling of Torsional Vibrations in Marine Powertrains

This paper discusses how stationary torsional vibrations in marine power trains with several connection points and branches can be modeled and analyzed. It has been found that increased demands on today's marine diesel engines, in terms of weight, compactness and high output have resulted in systems becoming ever more sensitive to torsional vibrations. Different types of dampers used to limit torsional vibrations in engine crankshafts have been studied.

The analyses performed show that engine irregularity and propeller excitation cannot be disregarded in torsional vibration analyses of marine drive trains. Engine irregularity in this context is the phenomenon that occurs when there is a stochastic variation of cylinder pressures within one engine.