Study On Magnetorheological Damper And It's Application To Structural Vibration Control

Structural vibration control is a new kind of anti-earthquake technique. Using magnetorheological damper (MRD) to control structural vibration is one of effective methods. The advantages of magnetorheological damper (MRD) are not only simple structure, small volume, quick respond, small power requirement and adjustable damp force, but also easy combination with computer. There are a large amount of researches on the MR damper and their applications up to now, and many significant achievements have been gained. However, there are many problems required to be further investigated including simulation for mechanical performance of MR damper, analysis of structure with MR damper etc., so these problems need to be further completed and solved.In this paper, mechanical performances of MR damper and vibration control of structure with MR damper are analyzed theoretically and investigated experimentally. The main efforts are devoted to the following aspects:Experimental study on the damping characteristics of MR damper is carried out. A strong hysteresis of damping force vs. damper displacement is observed, which indicates that the MR damper is a good energy-dissipating device. In addition, the force vs. velocity behavior shows distinct pre-yield nonlinear hysteresis characteristics in low speed region and linear relation in high speed region. Furthermore, a nonlinear damper model is constructed based on the testing results. The model parameters are identified from a set of experimental data, and vary with different exciting frequencies and applied currents for various test cases.The control law for the seismic passive control response analysis of the building with passive MR damper control system is presented, and the relevant mechanical analysis and computational model are set up. Then, the effects of vibration control with MR damper are verified by using the time-history analysis of the seismic response of structural systems with passive control. Moreover, various factors affecting the control results are analyzed and discussed in detail.A four-storey steel frame model with MR damper at first floor is put on the shaking table to study the dynamic response. The results show that MR damper can decrease the response of the model above 80%, especially when the frequency of input wave is close to the frequency of model. The Device can effectively control the response of model. Compared with the results of experiment and numerical simulation, it is found that they are concordant with each other, and which proved the numerical simulation used in this paper to be reliability.