The damping effect of magnetorheological elastomers on dynamic absorber for powertrain vibration reduction

The effect of damping of magnetorheological elastomer (MRE) on effectiveness of Adaptive Tuned Vibration Absorber (ATVA) for vehicle powertrain torsional steady vibration reduction is presented in this study. The MRE used to develop the ATVA is a soft MRE with a significant MR effect (the increase in elastic modulus is about 100 times). Thus, the ATVA can work in a wide frequency bandwidth. Several damping models were used for the soft MRE to estimate and compare the ATVA effectiveness for vibration reduction of a powertrain which is modeled as a four-degree-of-freedom system. Also, approximated formulas for both shear modulus and damping are proposed for ATVA design and they are in agreement with experiment data. The numerical simulations of the powertrain system fitted with the ATVA are carried out for these damping models. The obtained results show that at the resonant frequency the less MRE damping ratio is the higher ATVA effectiveness could be. However, the results also indicate that a low damping ratio may result in high vibration responses at the two new invariant frequencies which are introduced after adding the ATVA to the powertrain system. Furthermore, the results showed that it is different from traditional absorbers for tuning ATVA damping ratio and stiffness coefficient because for ATVA using MREs when either stiffness or damping coefficient is tuned, the other one will be set automatically as well. This result will be useful for choosing an optimal MRE material for constructing a smart ATVA for powertrain vibration reduction.