The Development Of The Simulation Bench For Ship Propulsion Shafting System And The Research On The Characteristics Of Longitudinal And Transverse Coupled Vibration

Due to the mechanism of the apparent low-frequency line-spectrum vibration in the stern of the ship is unknown,especially the vibration characteristics of the low-frequency linespectrum vibration caused by the vertical and horizontal coupling effect of the propulsion shaft system have not been fully grasped,the domestic ship’s propulsion shaft system has lowfrequency coupling vibration and large noise.Poor running stability and eccentric wear of bearings.Moreover,the ship’s propulsion shaft is long and the internal structure of the hull is complicated,which exacerbates the complexity of the above-mentioned problems.Therefore,it is necessary to carry out research work on the generation mechanism and vibration characteristics of the longitudinal and transverse coupled vibration of the ship’s propulsion shafting.In order to better carry out experimental research and analyze the vibration characteristics of the ship’s propulsion shafting,this paper has completed the engineering design and developed the ship propulsion shafting simulation scale-down bench,constructed the longitudinal and transverse coupled vibration model of the ship’s propulsion shafting.The numerical method and analytical method are used to study the characteristics of the longitudinal and transverse coupled vibration of the shafting system,and on this basis,measures to reduce the longitudinal and l transverse coupled vibration of the shafting system are proposed.At the same time,set up a shafting vibration test bench,carry out shafting vibration experiments,and reproduce and verify the coupling vibration characteristics of the shafting.The specific research content of this article is as follows:(1)With reference to the structural parameters of a certain type of ship’s multi-support shafting,following the principle of similar dynamics and statics between the two shaftings,the original shafting structure is scaled down and equivalently replaced,and the ship propulsion shafting simulation scaled bench is designed.The calibration calculation of the shaft system of the simulation scaled-down bench is carried out,and the curve calibration process is proposed to guide the installation and debugging of the shaft system,and the performance test of the shaft system after the debugging is carried out to prove the effectiveness of the calibration installation method.(2)Design the measurement method of the deflection axis of the shafting system,take the non-diffracted light as the reference,use the grating displacement sensor to measure the deflection difference of each measuring point,and use the CCD camera to measure the nondiffracted light to correct the deflection difference of each point,so as to obtain an accurate measurement axis,compare the measured axis with the theoretical axis to further test the effect of shaft alignment and installation.(3)Based on the mechanical properties of the plane beam element,a longitudinal and transverse coupled vibration model of the ship’s propulsion shaft system considering the boundary conditions is constructed,and the model is analyzed by numerical and analytical methods.Taking the simulation of the scaled gantry shaft system as an example,the amplitudefrequency characteristics of the longitudinal and transverse coupled vibrations are studied,the influence of the parameters of the shaft system and the alignment factors of the shaft system on the coupling vibration is explored.The reduction measures of the longitudinal and transverse coupling vibration of the shaft system are put forward from three aspects: weakening the longitudinal and transverse coupling effect,frequency modulation or setting the no speed zone,and good alignment of the shaft system.(4)Set up a simulation bench shafting vibration test bench,based on the results of theoretical analysis,conduct experiments on the free vibration and longitudinal and transverse coupled vibrations of the simulation scale bench shafting to verify the correctness of the theoretical analysis and reproduce the longitudinal and transverse shafting coupled vibration phenomenon.