Research On Control Of Non-stationary Vibration Of The Shafting With Stiffness-changing Dynamic Absorber

Vibration of the shafting leads to problems like noise radiation andstructural fatigue damage, and it usually becomes intensified when therotary rate changes as during the period of starting-up and stopping. Sincethis kind of vibration belongs to non-stationary vibration arising fromvarious reasons, there lack a unified theoretical description andparticularly lack effective measure for its control. The research work inthis thesis is focused on this specific subject. On basis of the theoreticalmodels established for practical vibration systems, we present controlscheme that applying dynamic absorber of changing-stiffness. The relatedalgorithm are devised and tested via numerical simulation for a motor anda shafting of ship power system. The detailed works are as the following:Firstly, this paper makes a survey on research status of variousstiffness control technologies with analysis of working principles andcomparison of their performances in variant range of stiffness andresponding speed as well as reliability. Then research was done based on non-stationary vibration in thestart-up process of the motor. The quasi-steady algorithm and thegenetic algorithm was adopted and contrasted, and then an improvedquasi-steady approach for varying stiffness was proposed.At last, a non-stationary theoretical model of longitudinal vibrationof ship shafting was put forward. An effective theoretical calculationmethod for a shaft was proposed and was then verified by finite elementsoftware. The improved quasi-steady approach was applied to ship shaftlongitudinal vibration. Then its effectiveness was verified comparativeanalysis.Taking into account specific structure of the ship shaft longitudinalvibration, a variable stiffness vibration absorber made of MRE forreducing the ship shaft longitudinal vibration was proposed.