Vibration Control Of Base-Isolated Structures With Neural Network And Fuzzy Logic Alogrithm

Structures are probably damaged beyond rehabilitation,even collapse during high intensity earthquakes.As one of the most widely used anti-seismic methods of structures,base-isolated technique is also the earliest approach applied in this field.However,the displacement of the isolation layer of the base-isolated structures is much larger than that of the fixed base structures when they are subjected to identical earthquake ground motion,especially under the pulse near-fault excitations.In virtue of this phenomenon,structural reliability is affected to a certain extent.Consequently,it is necessary to investigate the vibration control methods of the base-isolated structures subjected to earthquakes,in order to improve the earthquake resistance of isolated buildings.In this paper,a magnetorheological(MR)damper is adopted as the damping control device,strengthening the anti-seismic performance is regarded as the purpose,the study is divided into three parts as follows:A semi-active control method is proposed utilizing artificial neural network algorithm and fuzzy logical algorithm on the basis of the characteristics of MR damper.A neural network controller is created as a predictive controller in order to identified the inputted ground motions and forecast the response of buildings during earthquakes.Realizing the real-time adjustability of the control force implied on buildings owes to the fuzzy logical controller which is created to generate a more proper command voltage of the damper.The mechanical models of the isolation bearings and MR dampers are summarized,the numerical analysis model of base-isolation structure is established,the numerical model of the semi-active control structure is established with the neural network controller and the fuzzy controller,and the characteristics of different kinds of excitations are analyzed.In the light of characteristics of earthquake ground motion and the principles of selection,a few emblematical earthquake ground motions are selected,including pulse-type near-field earthquakes,non-pulse-type near-field earthquakes,far-field earthquakes.Numerical analysis of the base-isolated structure is carried out,according to the response evaluating indicators,the damping effect of the proposed semi-active control method is comparatively analyzed.The experimental results indicate that the proposed neural-fuzzy logical semi-active control strategy can significantly diminish the isolation layer displacement under different types of earthquakes,and the purpose of major structure protection is achieved.