Effect of frequency dependence of large mass ratio viscoelastic tuned mass damper on seismic performance of structures

This paper investigates the effect of the frequency dependence of the large mass ratio viscoelastic tuned mass damper (VTMD) on the seismic performance of structures. Compared with conventional TMDs, the frequency dependence of the complex stiffness of VTMD affects its control performance but is always neglected in the seismic analysis of structures. A linear function is introduced to describe the frequency dependence of the real stiffness of the VTMD. An indicator is defined to quantitatively characterize the frequency dependence level of the real stiffness. The effects of the frequency dependence on the control effectiveness and robustness are illustrated by a two degree of freedom (DOF) system under the Gaussian white noise excitation. At last, a numerical simulation of a five-story frame structure under real earthquakes and filtered white noises is presented to illustrate the mitigation effect of the large mass ratio VTMD under different ground conditions. The results show that the frequency dependence level of the VTMD depends on both the type of viscoelastic materials and controlled modal frequency. In the fundamental mode response mitigation, the frequency dependence of the real stiffness improves the control effectiveness and robustness of the VTMD, while in the non-fundamental mode response mitigation, the control effect of the VTMD is weaker to that of the conventional TMD because of the damping characteristic of the complex stiffness element.