Theoretical research on ship shafting torsional vibration based on power flow theory

As an indispensable component of the ship, marine shafting system transmits power generated by the main engine to the propeller, and at the same time transmits propeller thrust to the hull, and therefore drives the ship ahead. Torsional vibration does lots harm to ship shaft system, brings a serious threat to the safe navigation of the ship. The method of power flow considers the amplitude and phase of force as well as response in the system, reveals the vibration transmission mechanism in the aspect of power, which overcomes the limitations of the traditional method. In this paper, we introduced the power flow theory and its energy and partial balance equations, proposed the power flow distribution calculation method of ship propulsion shafting torsional vibration based on the theory of power flow, and conducted the finite element analysis. From the perspective of theoretical analysis and finite element simulation, we studied the power flow distribution characteristics of typical shafting macro power distribution and micro power flow transfer, thus to provide methods and technical supports for the ship condition monitoring and fault diagnosis.