Performance evaluation and comparison of magnetorheological elastomer absorbers working in shear and squeeze modes
The adaptive tuned vibration absorbers based on magnetorheological elastomers are mainly developed in shear and squeeze working modes. The distinctions between the two kinds of magnetorheological elastomer absorbers are less investigated. In order to investigate the distinctions induced by the working mode, two magnetorheological elastomer absorbers working in different modes are theoretically and experimentally analyzed in this article. Magnetorheological elastomer was first prepared and tested in shear and squeeze modes by parallel-plate rheometer and materials test system, respectively. Then, the fabricated magnetorheological elastomers were used to develop absorbers working in shear and squeeze modes. The performance of these two absorbers at various magnetic fields is characterized under swept excited frequencies by using a vibration testing system. The experimental results illustrate that the natural frequency of the magnetorheological elastomer absorber working in shear mode can be tuned from 32 to 62 Hz, while the variation range of the natural frequency of the magnetorheological elastomer absorber working in squeeze mode is from 62 to 127 Hz, which indicates the squeeze magnetorheological elastomer absorber has larger frequency-shift range than the shear magnetorheological elastomer absorber. Then, two theoretical models are presented to investigate and predict the frequency-shift performance of the two magnetorheological elastomer absorbers. The theoretical analysis results further verify the above conclusion.