Evaluation of a nonlinear TMD seismic performance for multi-degree of freedom structures

The aim of this study is to evaluate the performance of a recently proposed tuned mass damper (TMD) to control seismic demands of multi-degree of freedom (MDOF) structures. The TMD is composed of a mass, a viscous damper, a linear spring, and a shape memory alloy (SMA)-based nonlinear stiffness unit. The performance of the TMD is compared to that of a conventional linear TMD while both embedded on three different lumped mass shear models (6, 10, and 25 stories). The numerical analyses of the structural models are carried out subjected to broad-band excitations involving 50 far-field ground motions and a filtered Gaussian white noise. The results show that the nonlinear TMD, which benefits from gradually increasing hysteretic damping in addition to viscous damping, performs better than the linear TMD, especially for longer structural periods. However, the damper mass displacement in the nonlinear TMD is not significantly higher than that of the linear TMD. Furthermore, the height-wise distribution of structural responses obtained from various TMD tunings confirms that the different optimization objectives used for the nonlinear TMD tuning do not significantly affect its seismic performance. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.