Analysis of the power flow transmission characters of large marine propulsion shafting system

Marine shafting system is the indispensable component of a ship power plant. As the "heart" of the ship, marine power plant provides propulsion and secondary energy for normal navigation, operations, combats, and other needs of the ship it. Compared with the classical vibration analysis and the oil analysis theory, the method based on power flow is easier to explain the energy distribution and transmission mechanism. Proposed a computing method for shaft system energy distribution of large ship propulsion shafting under torsional vibration, axial vibration, and whirling vibration and coupled vibration based on the theory of the power flow in the paper. According to the theory of power flow, the dynamic equation, constitutive equation, the relationship between displacement and strain, the relationship between displacement and velocity, and boundary conditions of a typical bar under the action of tension and compression, torsion and bending is provided. Combining with the bond graph theory, the bond graph model of the 8530 TEU container ship propulsion shafting is established. Based on the theories above, the power flow calculation formula of the shafting under longitudinal vibration, torsional vibration, whirling vibration and coupled vibration of different boundary conditions is deduced.