Research On Vibration Power Flow Transfer Characteristics Of The Propulsion Shafting-hull Coupled System

The engine-propulsion shafting-propeller is a kind of propulsion system which is adopted widely in all kinds of ships.The propulsion shafting is a bridge linking the power source and the propelling object.It plays an important role,and the vibration of the shafting has an important influence on the ship's navigation and safety.Therefore,the study of the vibration characteristics of the coupled system of the shafting and the hull has theoretical guiding significance for the design and maintenance of the propulsion shafting.It is of great engineering value and military significance to improve the safety of the ship.On the basis of investigating the domestic and foreign research status of the propulsion shafting at home and abroad,this paper combines with the general mechanical structure coupled with the shafting and its hull,the vibration power flow transmission law corresponding to the three types of vibration modes of the transmission shaft,such as torsion,longitudinal and bending,for the complex coupling system composed of propeller shaft and shafting and hull support hull is studied theoretically.It includes the establishment and comprehensive solution of the subsystem vibration differential equation,the calculation method of the system vibration energy and the transfer power flow,the corresponding numerical calculation and the analysis of influence factors,etc,so as to provide the theoretical reference for further promoting the coupling vibration damping design of the shafting and the hull and the vibration and noise detection and analysis.Firstly,with reference to the theoretical research method of the mechanical structure of the propulsion shafting and the coupling vibration of the hull,the propulsion shafting and the hull coupling system are decomposed into several substructures,such as the propeller shaft shaft coupling and the hull joint bearing hull,and the hull is simulated by a cylindrical shell.The dynamic transfer relationship of the above substructures under the torsional,longitudinal and flexural vibration of the propulsion shafting is analyzed,and the vibration differential equations of each substructure are established by means of the wave method and admittance method.Secondly,the Fourier transform and admittance method are used to solve the differential equations of the differential equations of each substructure of the system under the torsional,longitudinal and bending vibration of the transmission shaft,and the calculation method of the transmission power flow and the vibration energy of the shaft system in the coupling links is theoretically derived according to the principle of the vibration power flow analysis.Lastly,On the basis of the above work,combined with an example of the coupled vibration analysis of a propulsion shafting and the hull,the Matlab software is programmed and calculated.The transmission characteristics of the vibration power flow in the transmission path composed of the transmission shaft and its hull coupling support are studied and analyzed.The effects of the seed structure parameters,including the propeller,the drive shaft and the elastic joint unit,on the power flow transmission and the vibration energy of the three types of shafting,which are torsional,longitudinal and bending,are analyzed and summarized.