Study Of Simulation And Experiment On Dynamic Performance Of Marine Propulsion System Considering Multi-factors

Nowadays,the ship being acted as an important long-distance transport tool,its reliability,safety and efficiency have gained more attention.However,dynamic characteristics of ship propulsion system always changed unpredictably because of the complexity of working environment and diversity of influence factors,which caused the unreliable navigation.This paper analyzed the influence of these factors on dynamic characteristics of ship propulsion system by co-simulation based dynamic model and platform experiment.The main dynamic parameters discussed in this paper torsional vibration and the axis locus which can be affected by these factors,like ship hull deformation,external incentives and oil film.The main research contents and results of this thesis are as follows:(1)The dynamic software ADAMS is used to built ship propulsion system combining with Ansys.And ship hull deformation is considered in the model to analyze the influence on the torsional vibration.The results indicate that ship hull deformation has great effect on torsional vibration.The smaller the distance between bearing and propeller,the more influence on torsional vibration.And the different sea states have different effects on torsional vibration of ship propulsion system.The peak of torsional vibration increases with the increasing of ship speed and wave height.But for angle of wave approach,the second peak is highest when angle of wave approach is 90 degree;the second peak is lower when angle of wave approach is 0 degree or 180 degree.(2)The dynamic software ADAMS is used to analyze the influence of incentives on torsional vibration.The results show that the resistance torque caused by propeller makes the most important effect on torsional vibration and axial thrust also has some effect on torsional vibration,especially in low frequency area.Of all incentives caused by diesel engine,the smaller the distance between cylinder and propeller,the more influence on torsional vibration.(3)The dynamic software ADAMS is used to simulate the influence of oil film on ship propulsion system combining with Matlab according to the non-dimension Reynolds equation.The variation of axis locus on bearing and influence of oil film are discussed by co-simulation.The results indicate that the existence of oil film in simulation can avoid the unnecessary contact between bearing and shaft and make the curve of axis locus smoother which more correspond to actual fact.(4)In order to check the simulation,the vertical or lateral displacements on intermediate bearing or stern bearing are used as simulated excitations caused by ship hull deformation or external incentives respectively in experiments based on small-scale ship propulsion system experiment table.The experiment results indicate that ship hull deformation and external incentives have more obvious effect on torsional vibration.But incentives of different directions on different position cause different peak frequency.So there are more peaks appearing when multi-incentives are applied.(5)The multi-body dynamic model is built based on small-scale ship propulsion system experiment table.Compare with the experiment results,the simulation results obtained from the model have the similar change tendency.Although the slight differences on torsional vibration,the differences in peak frequency are still reasonable and acceptable.And the axis loci obtained from simulation are almost the same with experiment results.So the comparison between simulation and experiment verifies the validity of the simulation method.