Abstract:
In recent years, energy dissipation devices based on the inerter have received great attention in the field of structural vibration control and isolation. A novel Crank Train Inerter (CTI) is studied in this paper. It is composed of a crank, a linking rod, a gearbox and a flywheel, and has the advantages of convenient adjustment of the inertance and strong displacement compatibility. The CTI device and its arrangement with the isolation bearings in anti-seismic bridges are proposed. The analytical expression of inertance of the CTI and the linear approximation condition is derived. A prototype CTI with different inertances is manufactured for mechanical performance tests under different working postures. The vibration control performance of CTI is verified in the seismic design of a three-span continuous beam bridge with variable cross section by numerical simulations, and the parameter design method for CTI is proposed. The results show that the CTI can be approximated as a linear inerter on the condition that the maximum displacement of the structure is less than 0.312 times of the crank length, while the length of the linking rod is greater than 1.803 times of the crank length. The inertances obtained from the tests are consistent with the theoretical results. The inertance can be adjusted by changing the crank length, while it would not be affected by the posture of the linking rod in the linear working range. The seismic responses of the bridge substructure can be reduced by combining the isolation bearings with the CTIs, which enlarges the deformation and energy dissipation of the isolation bearing without unseating.