Study On Torsional Vibration Of Shafting Considering Variable Inertia Of Adjustable Pitch Propeller

The adjustable propeller can make full use of the whole power of the main engine under any navigation conditions.Without changing the speed of the main engine,it can adjust the pitch to adapt to the various navigation states of the ship,improve its maneuverability and maneuverability.As an important component of the propulsion device of the ship,the operation safety of the adjustable propeller propulsion shafting is related to the safety of the ship navigation,so it is very necessary to make full use of it Torsional vibration calculation of shafting.In this paper,the propeller shafting of a bulk carrier is studied.Firstly,the method of simplifying the propeller shafting into an equivalent system is studied,and the inertia,damping,stiffness and excitation moment of the shafting components are calculated.Secondly,the three-dimensional model of the adjustable propeller is established,and the finite element model,the coupling model and the finite element model of the adjustable propeller are established by using workbench,The attached water inertia under the condition of full pitch of adjustable propeller is calculated by modal analysis and harmonic response analysis,and compared with the attached water coefficient recommended by classification society and manufacturer;the finite element model of propulsion shafting is established by ANSYS,and the influence of the variable pitch of adjustable propeller,silicon oil damper and cylinder flameout on the inherent characteristics of shafting is calculated and analyzed Thirdly,the torsional vibration calculation model and calculation method of shafting are studied.Based on the theoretical knowledge of shafting vibration calculation,C and MATLAB are used Finally,the free vibration and forced vibration are calculated by using the developed software,including the natural frequency,relative amplitude and mode shape,critical speed,vector sum of relative amplitude,angular displacement of each mass point,stress of each shaft section and coupling torque,which are provided by the manufacturer The results of the calculation sheet are compared with each other,and the correctness of the calculation software is verified.Two optimization schemes are provided to reduce the vibration of the intermediate shaft which exceeds the instantaneous allowable stress,so as to ensure the operation safety of the propulsion shaft system.The influence of single cylinder flameout and two cylinder flameout on the torsional vibration of the shaft system is analyzed.In the case of single cylinder flameout,the vibration response result is related to the position of flameout cylinder.In the case of two cylinders flameout,the resonance stress of the shaft section caused by the strong harmonic is closely related to the firing order.