Torsional Vibration Analysis Of Ship Propulsion And Study Of Anti-Vibration Damping

Propulsion shafting torsional vibration is one of the combustion engine power unit malfunction reasons. The torsional vibration aggravated problems can cause crankshaft,intermediate shaft,propeller shaft and other shaft segment fracture can cause gear wear,tooth surface pitting,coupler damage,excessive noise and other issues. These all affect the dynamic property and safety of ship driving, so the propulsion shafting torsional vibration research has very important significance.According to the shafting vibration check of CCS, this paper refers to a lot of domestic and foreign research datas. It analyzes the propulsion shafting torsional vibration characteristics from various aspects to reveal the ship shaft torsional vibration characteristic comprehensive, putting forward own opinions and standpoints about certain factors about torsional vibration, putting forward some corresponding measures of anti-vibration damping about torsional vibration.This paper first researches the shaft torsional vibration calculating, establishing the ship shafting vibration mathematical model and studies the shaft vibration calculation with examples, analyzing certain factors of allowable stress and process putting forward own proposals and analysis of different results under simplified model; Second,the paper analyzes the ship shafting torsional vibration characterstics using element method, using ANSYS to establish shafting equivalent model to prove the feasibility of torsional vibration calculation. Then the paper establishes the shaft solid model using ANSYS, analyzing the vibration characteristics through modal analysis, considering influence of the harmonic torque on the vibration characteristics from different point of view. Analyzing the influence of bearing stiffness and coupling methods on the torsional vibration using ANSYS creatively. In addition ,in this paper some affecting factors of the shaft torsional vibration are discussed, such as single cylinder misfire and uneven firing,V-type diesel engine's using,multi-motor and propeller,gear boxes on the impact of torsional vibration,nonlinear factors and torsional vibration of propeller vibration coupled with the other conditions, etc. Finally, various measures are proposed damping and avoiding shaft vibration, such as adjusting the firing order, installing shock absorber to adjust coupling, adjusting the system stiffness and inertia in different aspects and speeding area differentiating and so on,some examples are proposed to analyzed.