Abstract:
The nonlinear torsional vibration differential equation of a marine diesel shafting subjected to impact force of expansion of vapour and water is established by means of Lagrange equation. According to the method of multiple scales for a nonlinear vibration, the first approximate solution and parametric condition of primary parametric resonance under constant speed operation of flywheel of the system and numerical results are obtained. The amplitude frequency response curves of the system are acquired. Numerical results on the influences of the impact force of water on the amplitude frequency response curves of the system are analyzed. The amplitude frequency response curve of primary parametric resonance is formed by two branches. It has a larger resonance zone. Adjusting damping can avoid the occurrence of primary parametric resonance. A simulation model of the system is established using Simulink and the simulation is carried out. It is pointed out that the primary parameter resonance of the system is in a stable state.