Study Of Influence Factor On Shipping Shaft Torsional Vibration Calculation

This paper studies the calculation methods of shipping shaft torsional vibration using Holzer method, and put great emphasis on to the factors that affect the basic process of calculation of shipping shaft torsional vibration. They are the most important formulas in calculation of shipping shaft torsional vibration, the mean indicated pressure, the perturbed moment caused by air and outside damp. The mean indicated pressure is the only parameters that will be used when calculate the simple harmonic quantity coefficient. The perturbed moment caused by air is also a very important parameter that will affect the calculation of the complex simple harmonic quantity coefficient. Outside damp is the main parameter in dynamic magnification coefficient calculation. This paper also rectified some mistakes in traditional calculation methods.In order to investigate into the characteristic of shaft torsional vibration when any single cylinder misfire and how that affects the main power propulsion system of a ship, the author puts forward a new way of calculation concerning the shaft torsional vibration when the mean indicated pressure of other cylinders remain unchanged. Calculation of MAN B&W 10L90MC and MAN B&W 6L60MC diesel engine is taken as an example in the course of analysis and comparison and some relevant suggestions are made on its management.