Robustness Analysis of Semi-Active Tuned Vibration Absorbers With Magneto-Rheological Dampers: An Experimental Study

This paper offers an experimental robustness analysis of a semiactive tuned vibration absorber (TVA) as well as a passive TVA. A conventional passive TVA is only effective when it is tuned properly; otherwise, it may amplify the vibrations of the primary system. In many practical applications, inevitable off-tuning of a TVA often occurs because of system’s operating conditions or parameter changes over time. For example, adding or subtracting external mass on the existing primary system results in changes in the system’s natural frequency. The frequency changes of the primary system are responsible for “off-tuning” of TVAs. When TVAs are off-tuned, their effectiveness is sharply reduced. In our experimental robustness analysis, we focused on the dynamic performance of both the passive and the semiactive TVAs when the mass of the primary system changed (mass off-tuning). To this end, a test apparatus was built to represent a two-degree-of-freedom structure model coupled with a TVA. The semiactive TVA considered in this study employed a Magneto-Rheological (MR) damper as its damping element to enhance overall performance. Using this test apparatus, a series of tests were conducted to identify the optimal tuning parameters of each of the TVAs. The optimal tuning parameters were obtained based on equal peak transmissibility criteria. The mass off-tuning tests were then performed on the optimally tuned semiactive TVA and the optimally tuned passive TVA. In order to off-tune the primary mass, the mass of the primary system varied from −23% to +23% of its nominal mass. The experimental results showed that the semiactive TVA with MR dampers are more robust to changes in the primary mass (off-tuning) than the passive TVA.