| Base isolation is an effective method to reduce the damage of civil engineering structures under earthquake,and it has received extensive attention from many researchers and engineering designers.Currently,the research and application of the base isolation structure in the world are mostly based on the far-field and non-pulse-type near-fault earthquake.However,the vibration control research of the base isolation structure under pulse-type near-fault earthquake is less.In this paper,seismic reduction of the composite isolated structure with piezoelectric friction damper under pulse-type near-fault earthquake is studied.The primary innovative contents include:Typical pulse-type near-fault earthquakes are selected from the ground motion database,and the characteristics of them are studied.In order to carry on the comparative analysis of response spectrum,the corresponding non-pulse-type near-fault earthquakes and the far-field earthquakes are selected.According to the characteristics of piezoelectric friction damper,this paper proposed a novel adaptive fuzzy logic control strategy.This control strategy includes a higher-level controller and a sub-level controller.The higher-level controller is implemented to identify the characteristics of seismic input such that the sub-level controller can effectively determines the command voltage of the piezoelectric friction damper according to the level of earthquakes.A composite isolated structure model and its evaluation index are established.The uncontrolled situation and the passive control situation are also studied for comparative analysis.The results show that adaptive fuzzy control strategy can not only significantly reduce the displacement of isolation layer but also effectively reduce the response of superstructure.In addition,the adaptive control strategy has better earthquake mitigation effect and adaptability for the composite isolated structure under different types of earthquakes. |
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