Vibration characteristics of a marine propulsion shaft excited by the effect of propeller and diesel

The propulsion shaft system is one of the most important parts of marine power plant, the reliability and stabilization of which effects the security of the ship operation directly. The forced vibration introduced by the external excitation makes the vibration characteristics of the propulsion shaft more complicated. Even the resonance phenomenon will occur. This paper mainly studies the vibration performance of the propulsion shaft introduced by the coupling effect of the propeller and diesel. Firstly, the empirical formulas of the exciting force introduced by the diesel and propeller are given. Then a finite element model of propulsion shaft is established with ANSYS. Meanwhile the dynamic responses of the shaft introduced by the diesel excitation, the propeller excitation and the coupling effect of the two excitation are obtained respectively. The research results show that well matched diesel-propeller contributes to the vibration reduction of the propulsion shaft.