Damage Spectra Of Base-isolated Structures Considering Non-proportional Damping And Hysteretic Energy Dissipation

The damage spectrum comprehensively considers the characteristics of the structure's first overrun failure,low cycle fatigue failure and hysteretic energy consumption,which can better reflect the actual damage degree of the structure under the action of earthquake.In recent years,domestic scholars have begun to study the damage spectrum and influencing factors of isolated structures,and have proposed a damage model of seismic isolation bearings considering the compression-shear correlation and tensile effect.The damage spectrum theory system of the base-isolated structure is still in the process of continuous development and improvem ent.At this time,It is especially important to set up a damage spectrum suitable for long periods and considering the non-proportional damping of isolated structures.In this paper,by establishing a calculation formula that characterizes the damage spec trum of the isolated structure,the change trend of the damage spectrum is studied to serve engineering practice.The specific research work is as follows:(1)Establish three analysis models to characterize the isolated structure,including single particle model,double particle model and finite element analysis model.(2)The calculation formula of nonlinear single particle damage spectrum based on Bouc-Wen model is established,and the solution process is derived by incremental Newmark-? method,which is solved by MATLAB programming.(3)Study on nonlinear single particle damage spectrum and verification of calculation formula.El-Centro wave,Taft wave,Northrige wave and Kobe wave are selected to study the effect of the difference of the pseudo-acceleration spectrum(Preso)and the acceleration spectrum(Abs)on the damage spectrum of nonlinear single particle system,and the Northrige wave and Kobe wave are used to analyze the nonlinear dynamic time history of the finite element model with a certain period,by comparing the damage value obtained by Bouc-Wen model with the damage value obtained by nonlinear single particle damage spectrum evaluation,it is found that the damage value is in good agreement,which verifies the accuracy and rationality of the calculation formula of nonlinear single particle damage spectrum.(4)Based on the Zonal Rayleigh damping model,the linear response spectrum model of the double-particle isolation system with non-proportional damping is given,and the nonlinear double-particle damage spectrum of the isolation structure is calculated by using the John William Strutt,3rd Baron Rayleigh Damping Model,the state space method is used to express the dynamic equation and MATLAB is used to program.The response is solved by Runge-Kutta method and the damage spectrum of base isolation structure is obtained.(5)Study on damage spectrum of isolated structure based on double particle model.By using the method of big data statistics and considering the randomness of seismic records,the changing trend of double particle damage spectrum under four kinds of sites near-field pulse earthquake is studied.It is concluded that the damage spectrum of the four types of sites is similar and tends to decrease.Before 4s,the site type has obvious influence on the damage spectrum of the structure,and the response increases with the increase of the period,after 4s,the damage value tends to a certain value.