Experimental and numerical studies of a novel track bistable nonlinear energy sink with improved energy robustness for structural response mitigation

摘要

This paper proposes a novel track bistable nonlinear energy sink (track BNES) to solve the energy-dependence issue in conventional NESs, which utilizes the track configuration to form nonlinear restoring forces featured by both the peaking behavior and negative stiffness. Due to these unique features, the functional energy range of the track BNES is extended toward both the upper and lower ends. Based on the mathematical representations of the device, the track BNES is designed and experimentally investigated on a small-scaled three-story steel frame structure. Subsequently, the control performance of the proposed track BNES is evaluated on the basis of the validated numerical model. A systematic study of the track BNES is carried out in comparison with four comparable mass dampers when the primary structure is subjected to impulsive and seismic excitations. The results show that the track BNES has the same control effectiveness as the existing devices considered but exhibits stronger robustness against changes in both the structural properties and energy levels. By utilizing both nonlinear and linear dynamics to its advantage, the track BNES system produces relatively small structural responses with acceptable stroke demands. The study demonstrates the great potential of track BNESs as a favorable control strategy for seismic response mitigation of structures.