Abstract
The authors have studied the torsional vibration characteristics of a crankshaft system consisting of a six-cylinder engine for a large ship which has a five-bladed propeller in the case where one cylinder misfires. In such a case, the amplitude of torsional vibrations due to the sixth torsional harmonic reduces compared with that in case of a normal operation. However, the forth and fifth torsional harmonics increase; therefore, the amplitude of the torsional vibrations corresponding to these components also increases. In particular, the torsional vibration stress due to the forth torsional harmonic component increases; therefore, it is necessary to ensure that the allowable stresses on the shaft are not exceeded.
