Design And Analysis Of Dynamic Vibration Absorber With String-Permanent Magnet Mechanism

Rotating machinery,such as aeroengine,large air compressor,steam turbine and so on,is the essential equipment in the national industrial sector.Its application range is wide,including national defense,civilian use,business and so on.The most serious problem of rotating machinery,when it is working,is the large amplitude of the vibration which resulting in a huge noise,bearing damage and other serious phenomena.The resonance phenomenon make more serious destruction of rotating machinery,and the amplitude will increase sharply when the rotating machinery works in the over-resonance frequency.How to reduce or suppress the resonance vibration is of great significance.Vibration absorber is a common structure which can reduce the resonance amplitude.Although it can reduce the resonance damage,but its still has many defects,such as the small frequency range,adjust inconveniently and so on.These greatly affect the practical performance of the vibration absorber.In order to solve the above problems,this paper presents the structure of tension string-permanent magnet variable stiffness absorber.The vibration absorber improves the use range of the vibration absorber,and the frequency of the lowest amplitude point can be changed.The vibration absorber can solve these problem.The main research contents are as follows(1)Design a vibration absorber composed of strings and permanent magnetic mechanism,which combines negative stiffness with positive stiffness together.By using the new vibration absorber which uses the form of positive and negative stiffness parallel,the frequency range of the dynamic vibration absorber is lager than before.(2)Incremental Harmonic Balance method(IHB)is applied in the following analysis the model of the rotor test-platform,including the negative stiffness producing mechanism using ring type permanent magnets and the positive stiffness of the strings.At the same time,the effect of the two factors on the response of the rotor system is analyzed separately.(3)Changing the frequency of the antiresonance point is one of the main characteristics the dynamic vibration absorber by changing the internal stress of the strings,and the resonant amplitude of the rotating machine is effectively reduced.The repeatability and feasibility of the application of tension string-permanent variable stiffness mechanism are verified through the experiment.The influence of the system on the response of the rotor system is analyzed in this paper.(4)The experimental results are in good agreement with the numerical simulation results.Based on the experimental results and analysis,the new dynamic vibration absorber's characteristics are verified.Stepper motor and screw structure is used to adjust easily and improve accuracy.