Tunable broadband low-frequency band gap of multiple-layer metastructure induced by time-delayed vibration absorbers

In this study, a low-frequency multiple-layer metastructure is proposed for broadband vibration control. The effects of the time-delayed vibration absorbers (TDVAs) on the dynamic characteristics of a nonlinear metastructure are explored. First, the effect of using a single TDVA on the metastructure for vibration suppression is studied. The results show that the introduction of time-delayed feedback control is beneficial to improve the vibration suppression of the metastructure in the anti-resonance range. Then, the relationship between the dynamic response of the metastructure and the control parameters of the multiple TDVAs which are evenly distributed is explored. The relationship between the effective vibration suppression frequency band and the control parameters is given. From the results in this study, it is found that the introduction of equivalent damping by time-delayed control can achieve a significant broadening of the effective vibration suppression frequency band. The band gap can be expanded to more than twice its original width. Although the vibration suppression effect in the effective frequency band is slightly deteriorated, the widening of the bandwidth still has important significance. This study gives the method of parameter selection of TDVAs in the multi-degree-of-freedom nonlinear system.