Performance Study Of Dynamic Vibration Absorption With Adjusted Frequency Based On Gyroscopic Effect

For ship using gas turbine or steam turbine power plant,which sailed high maneuverability.The propeller needs to operate the speed of wide range.In some of water area,it is necessary to consider higher harmonic excitation force,so the frequency range is even greater.So the submarine resonance does not occur in such a wide frequency range is difficult.This paper designed a dynamic absorption isolator in order to solve the problem of ship vibration.A self-rotating pendulum model is built inside the system,which adopted the flexible supporting at one end and rigid supporting at the other end.The gyroscopic effect occurred during the work process of the rotor.Therefore,the system rotational speed is changed in order to change the natural frequency of dynamic absorption isolator,in which way the natural frequency might be equal to or similar to the excitation frequency of the forced vibrated system and the amplitude of the forced vibrated system can be controlled.Firstly,dynamic equation of a rotor with the flexible supporting at one end and rigid supporting at the other end is built.Through calculation,a curve illustrating the relationship between the system natural frequency and the rotational speed was obtained.The model was verified by experiment and the error was analyzed.The accurancy of the model was proved which laid fundation for the establishment of dynamic absorption isolator.What is more,because the gyroscopic effect of the self-rotating pendulum model was unconspicuous,the natural frequency was optimized in order to obtain a large range of frequency under the circumstance of a relatively low rotation speed.Finally,the equation of dynamic absorption isolator was analyzed and verified by establishing the dynamic model and equation of the absorption isolator,on the basis of which the dynamic characteristics were analyzed and vibration damping effect with and without the isolator was showed,the amplitude ratio from 36.4 is lower to 7.3.The thesis also analyzed according to different damping ratio and rotation speed.The model of this thesis can be apply to dynamic absorption isolation of ship shafting,which may help to get a better absorption amplitude and ensure a long time work.