Seismic Reduction Analysis Of Base Isolation Structure Based On Double Crossed SMA-LRB

Shape memory alloy(SMA)has been widely used in the field of civil engineering because of its shape memory effect and superelastic effect.As a seismic control technology,base isolation has been widely used in buildings and bridges.In this paper,combined with lead rubber bearing(LRB),based on the optimization of double-crossing SMA-LRB,the optimized model of double-crossing SMA-LRB is established,and the damping performance of isolation structure based on double-crossing SMA-LRB under different earthquake intensity is studied.The main research contents include:(1)Presenting an investigation on the effects of strain amplitude,loading rate,temperature change and other factors on the mechanical properties of SMA.A program of stress-strain relationship of SMA was developed,and the indicators of single-turn energy,equivalent secant stiffness,and equivalent damping ratio are compared and analyzed.The results show that the program can simulate the mechanical behavior of SMA well.(2)A program is compiled to analyze the performance of SMA in LRB bearings under different arrangements.Comparing the mechanical behaviors of SMA-LRB composite bearings under different loads The results show that compared with the single cross arrangement,the strain caused by double crossover arrangement of SMA is the largest,the hysteretic curves of double-crossed SMA are triangular,and the hysteretic curves of the improved SMA-LRB bearing are fuller.(3)The improved double-crossing SMA-LRB bearing is placed in the isolated structure,and the response of the isolated structure under different intensity earthquake is analyzed.The results show that,compared with that before improvement,the improved double-crossed SMA-LRB isolation bearing can effectively reduce the displacement of the isolation layer,and the bearing has stronger energy dissipation capacity and certain self-reset ability.