Structural vibration mitigation via hysteretic tuned mass dampers

Passive or semi-active systems exhibit a great potential for structural vibration mitigation because of low-power consumption requirements, fault-tolerance characteristics, and low-maintenance costs. In addition, they can be easily retrofitted into existing structures while maintaining the global structural flexibility. In the area of passive systems design, the concept of augmenting the original system with an auxiliary subsystem (comprised of an attached mass with a visco-elastic device or a pendulum-like system) dates back to several centuries ago. Den Hartog (1934) was the first to effectively design a linear vibration absorber based on an optimal frequency tuning condition and optimum damping coefficient. For harmonic or narrow-band excitations, the linear absorber allows significant abatement of vibrational energy. However, in the presence of mistuning of the absorber (either frequency- and/or damping-wise) or in the presence of broad-band excitations, the linear absorber performance is significantly degraded. As a mean to overcome the drawbacks of the linear visco-elastic TMD, the effectiveness of a hysteretic device - delivering the restoring force in the auxiliary system - has been investigated in (Lacarbonara and Vestroni, 2003). A large number of materials exhibits the potential for implementation in hysteretic devices such as suitably arranged traditional elastic-perfectly plastic materials (e.g., structural steel) or innovative materials (e.g., shape-memory materials, high-damping hysteretic rubbers, or polymeric materials with embedded carbon-nanotube dispersions). The present investigations, based on a parametric study of different material parameters characterizing softening, hardening or quasi-linear behaviors, show that the levels of vibration reduction achieved near resonance may be enhanced for appropriate hysteretic characteristics. Moreover, the system sensitivity to mistuning is reduced thereby rendering the proposed passive system more robust, and the TMD strokes are sensibly reduced with respect to linear TMDs. The feasibility of the hystertic TMDs is investigated considering multi-story buildings of low and high rise.