Track nonlinear energy sink for rapid response reduction in building structures

A new type of nonlinear energy sink (NES), termed a track NES, is proposed in this paper. The shape of the track over which the auxiliary mass moves determines the character of the nonlinear restoring force for the NES. After deriving the equations of motion for the track NES, numerical optimization is carried out for the system implemented in a two-degree-of-freedom primary structure. The optimization results are in the track shape of a fourth-order polynomial. The performance of the track NES is compared with an equivalent tuned mass damper (TMD) and the Type I NES, which utilizes a cubic restoring force. The results of this comparison show that the attenuation observed with the track NES is competitive with the Type I NES and is more robust against changes in the underlying structure than the TMD. Moreover, the track NES is more scalable and offers greater flexibility in prescribing the associated nonlinear restoring force.