MREs And Its Application In The Structure Of Semi-active Control

Vibration control has been applied to the field of civil engineering for40years and it has become one of the most effective measures to resist earthquakes, hurricanes and other disasters. Semi-active control has advantages of low energy consumption, great control effect and low maintaining requirement. Semi-active control has the most potential in vibration control field. Magnetorheological elastomer (MRE) is a new type of magnetorheological intelligent materials. MRE’s controllable magnetic properties bring it a vast application prospect in the field of semi-active control.To use the controllable magnetic properties of MREs, we study the preparation of MREs, the design and the performance test of a shear type MRE damper. Besides, we analyze the simulation results of semi-active control structure with MRE dampers. The main contents and results are listed as follows.①It is mainly proceeded from four aspects, which are the raw material, the ratio of raw materials, laboratory equipments and preparation processes. And then two kinds of MREs on different matrixes are prepared——MREs based on silicone rubber and MREs based on natural rubber.②A magnetic field generator is designed and prepared. The magnetic properties of that generator is tested. The test results show that the magnetic induction intensity reaches to0.654T, when the loading current of the field generator is2A. It means that the generator designed basically meet the design requirements.③Based on the universal testing machine, a compression performance test system is established. And by using the test system, the compression performances of MREs based on silicone rubber and that of MREs based on nature rubber are tested. The test results show that the compression modulus of the two kinds of MREs are increasing with the current. Meanwhile, the increasing amounts are decreasing. When the current reaches to1.5A, the compression modulus of the MREs are close to saturation. The relative MR effect of MREs based on silicone rubber is higher than MREs based on silicone rubber. With the increasement of deformation, the relative MR effects of two kinds of MREs tend to be decreasing.④A shear type damper is designed and prepared through the choose of work modes, material selection and magnetic circuit design. MREs based on silicone rubber are used in damper preparation. A performance test of the damper is carried on using the electro-hydraulic servo fatigue testing machine. The test results show that, in the same displacement, the higher loading amplitude of the damper leads to the smaller output force. And loading frequency has no effect on the mechanical properties of the MRE damper. When loading frequency is0.5HZ as well as the amplitude is lmm, the equivalent stiffness of the MRE damper increases by128.2%and the equivalent viscous damping ratio basically has no change with the loading current.⑤Simulation analyses on passive control structure and three kinds of semi-active control structures (PD control structure, LQR control structure and fuzzy control structure) are carried on. Simulation results show that the four control structures have great control effects on structure’s displacement response and acceleration response. And that control effects on displacement response is better than control effects on acceleration response. Under different seismic waves, there are no obvious regularity on the control effects of the peak response, but there are obvious regularity on the control effects of the root mean square (RMS) response. On the control effects of the RMS displacement response, LQR control structure has the best control effect, passive control structure and fuzzy control structure follows, and the control effect of PD control structure is the worst. On the control effects of the RMS acceleration response, PD control structure has the best control effect, LQR control structure and fuzzy control structure follows, the control effect of passive control structure is the worst.