Shaking Table Test Study On Smart Isolation System Of Negative Stiffness

In the area of vibration control, the hybrid method of negative-stiffness semi-active control and passive control can fulfill the advantages of both method and overcome their disadvantages. This kind of hybrid method is able to largely reduce seismic response of isolated structure. But the relevant research is still sparse. This article is aiming to complement the study of hybrid method of negative-stiffness semi-active control and passive control. And the main contents of this article are as following:1. Nonlinear time history analysis on a four floor steel frame model is executed in SAP2000, and the structure response of deferent controlled structure is reviewed. By comparison of the response of different controlled structure under seven seismic records, find that the response of negative stiffness smart isolated structure is 30% smaller than LRB isolated structure. And negative stiffness smart isolated structure has smaller standard deviation. That negative stiffness smart isolation system can do a better vibration control is proved.2. A magnetorheological damper has been designed and manufactured. And the correspondent control system has been developed on NI cRIO embedded system and Lab VIEW. Then the function of the MRD and its control system is verified via base performance test and negative stiffness test. The tests show that the maximum force output of MRD can reach 10 kN, the maximum negative stiffness can reach-0.22kN/mm, and the negative stiffness can be tuned in a range. The effeteness of self-made MRD and its control system is proved, and the specification of MRD system can fulfil the request of this 4-story frame model.3. A shaking table test is applied on the four floor steel frame model. Strain sensor, acceleration sensor and laser displacement sensor is utilized to measure the response of the structure. According the measured response, Compared analysis on different isolation method is executed. The analysis shows that the negative stiffness smart isolated structure has much smaller response than fixed structure. Mean top story acceleration is reduced by 64%, first story column foot stress reduction factor has maximum at 0.31, minim at 0.16, mean at 0.24 and standard deviation at 0.14. And the first story column foot stress reduction factor of LRB isolation structure has maximum at 0.40, minim at 0.24, mean at 0.32 and standard deviation at 0.20. It shows that the effeteness and robust of negative stiffness smart isolation system are both supreme over LRB isolation.