EXPERIMENTAL AND NUMERICAL STUDY ON ADAPTIVE ADJUSTABLE STIFFNESS TUNED MASS DAMPER

To improve the sensitivity of passive tuned mass damper (TMD) to frequency tuning, overcome the difficulty of frequency changing, and improve its control effect on vertical human-induced vibration of footbridges, an adaptive variable stiffness TMD is studied in this paper. The mass with an internal through hole is placed on the spring, and a cantilever beam is fixed on each side of the mass, to the left and to the right of a stepping push-pull rod. The stepping push-pull rod can adjust the length of the cantilever beam into the tunnel of the mass, which is the length of the free end, to change its stiffness, thereby realizing the tuning of TMD frequency. After TMD is added to the main structure, the spectrum of the main structure will be disturbed, and it is difficult to directly identify the natural frequency of the main structure. Therefore, this paper first introduces the mechanism of adaptive adjustable stiffness TMD, then proposes a frequency identification algorithm of main structure based on undamped two-degrees-of-freedom model, and then conducts model experiments of a footbridge with stiffness adaptive regulation and four kinds of human-induced vibration control; at last, the decoupled structural frequency identification of the footbridge experiment is simulated.