Experimental Study on the Nonlinear Vibration of a New Composite Magnetorheological Damping System

Magnetorheological shock absorbers provide poor damping force in shearing direction. Thus, a composite magnetorheological damper composed of a rubber spring and a magnetorheological damper is proposed to withstand shear loads. A new damper tester is designed to obtain the vibration signal of this damper under external excitation. The magnetorheological vibration-reduction system is a typical nonlinear system, which has higher requirements for information extraction. To obtain the deeper correlation between crucial parameters of the damper and its performance, the autoregressive higher-order spectrum model is established. The formulas of the autoregressive trispectrum and its two-dimensional slice spectrum, diagonal slice spectrum and one-dimensional slice spectrum are derived. Then, the characteristics of the trispectrum and its slices of a magnetorheological vibration-reduction system under different loading currents, working frequencies are discussed. The experiment results show that the composite damper has good performance compared with common rubber shock absorbers, and the higher-order spectrum and its slices exhibit different the distribution density of the spectral amplitude and the distribution of spectral peaks under different working states, which are closely related to the currents and frequencies. The higher-order spectra are effective to quantificationally describe nonlinear coupling, restrain gaussian noise and reserve phase components of the vibration system.