Seismic optimization of variable friction pendulum tuned mass damper with hysteretic damping characteristic

Abstract

A variable friction pendulum-tuned mass damper (VFP-TMD) with hysteretic damping characteristics was proposed. The mechanism of the proposed VFP-TMD demonstrated linear behavior and nonlinear properties. Further, the fully nonlinear (FN) and partial linear (PL) equations of motion of the structure with the VFP-TMD system were derived. The VFP-TMD demonstrated stable and excellent seismic mitigation capacities and stroke limitation functionality. Based on the fixed-point theory, the closed-form exact solutions to design parameters of an undamped structure with a VFP-TMD system subjected to the ground motion were presented for different performance indices. The parametric studies showed that optimal designed VFP-TMD can be perfectly tuned in the frequency domain, which proved the applicability of closed-form solutions. To better understand VFP-TMD with hysteretic damping, constant friction pattern and multi-stage variable friction pattern were proposed for comparison. In contrast with constant friction and multi-stage variable friction, VFP-TMD with hysteretic damping characteristic was significantly optimized by the closed-form solutions. To verify the effectiveness of the closed-form solutions on VFP-TMD, twenty sets of real earthquake records were conducted which exhibited the superiority of linear variable friction patterns on seismic mitigation simultaneously. Results showed that the optimized VFP-TMD had an “infinitely large bandwidth”, which enabled it to reach its full potential according to the excitation amplitude.