Study on seismic dissipation mechanism of inter-story isolation structure based on phase

Abstract

Owing to the existence of the isolation layer, a phase lag phenomenon occurs between the superstructure and substructure of a story isolation structure. This phenomenon causes a phase difference between the superstructure and substructure; furthermore, the generated phase difference has a significant impact on the structural damping effect. To study this effect, we established a two-mass model of an inter-story isolated structure, derived the phase difference formula, analysed the impact of the phase difference on the damping effect of the modelled inter-story isolated structure and obtained the optimal phase difference to achieve the best damping effect; in addition, we combined the principle of minimum base shear and optimal phase difference to optimise the damping of the structural isolation layer with different mass ratios. Based on the optimal damping, an energy balance equation was established from the viewpoint of energy. The energy transfer and consumption under different phase differences were analysed to further discuss the relationship between phase differences and the damping effect of the inter-story isolated structure.