Study On Nonlinear Spectrum Characteristics Of Magnetorheological Damper

Magnetorheological technology is one of hot topics for a lot of scholars inrecent years. It has brought new change to the vibration field. The vibration signal ofMR damper is much complex. Most properties are contained in vibration signals.Thetraditional signal processing methods are very difficult to explore the essence ofthings. The paper uses two tools of fractional Fourier transform and High-orderspectrum to research spectrum characteristics of magnetorheological(MR) dampervibration system for non stationary vibration signal and stationary vibration signal.Ithas practical significance for the improvement of the damper performance andpromoting of the application.Changing three main factors including the working current of MR damper andvibration frequency and vibration force to study fractional Fourier transform oncharacteristics of detecting non-stationary signal.To find out the contact between thefractional Fourier spectrum and MR damper parameters. Experimental results showthat fractional Fourier transform is a generalized version of common Fouriertransform.It can suppress gaussian noise and reveal the features of signals from timedomain and frequency domain simultaneously.Fractional fourier transform can beused to detect the single component or component LFM signals. As working currentand vibration frequency increase,optimal order of fractional Fourier transformreduces.Increasing of vibration force makes signal frequency components becomemore complex.Fractional Fourier transform can extract LFM signal componentsbetter during vibration of magnetorheological damper.Time series AR model is established with the use of the colored noise filtered byvibration signals collected,then signal processing tool of the trispectrum is introduced.The trispectrum slices are utilized for analyzing dynamic frequency characteristics ofMR damper.The results prove that increment of vibration frequency increases thedegree of nonlinearity of MR damper under certain conditions. In the case of theabsence of magnetic saturation, increment of working current decreases firstly and then increases nonlinearity of MR system. Changing the excitation force can makevibration of the system severe,increases the nonlinear coupling degree and ofamplitude MR damper,at the moment trispectrum can also be seen as energyspectrum of the system.Reconstruction bispectrum of the trispectrum is more intuitiveto show two frequency angle coupling and distribution information and make up thethe trispectrum shortage in the details.The trispectrum slices spectrum are combinedwith the characteristics of the power spectrum and two-dimensional slices,that canvisually distinguish frequency coupling information. One-dimensional slice of thetrispectrum can detailly descripe energy of the system in different frequencydistribution,depict reconstruction bispectrum interior details.The trispectrum and theslice are effective methods for the study on vibration characteristics of the MRdamper.Two methods have their respective advantages for vibration signal analysis ofMR damper,are mutual complement and make the conclusion more comprehensive.