Vibration Control with Nonlinear Rotating Inertial Mass Device

The authors have been carrying out numerical studies on the effect of a passive nonlinear absorber containing a rotating inertial mass (N-RIM). In this paper, the performance of this proposed absorber system when used for the base isolation of a building against strong earthquakes is presented. The N-RIM system consists of a strongly nonlinear stiffness and a rotating inertial mass (RIM). The study reveals a number of interesting and complex dynamic phenomena over a broad frequency range, including pitchfork and quasi-periodic bifurcations as well as a saddle node. It is shown that the N-RIM system does not require a large amount of damping even if the mass ratio is large. Furthermore the N-RIM system suppresses the response amplitude over a relatively broad frequency range in the case of large input motion. In conclusion, the newly proposed N-RIM system reduces structural response quite effectively.