Emulational Study On The Semi-active Control Using Magnetorheological Fluid Damper

The MRFD (Magnetorheological Fluid Damper) is a kind of intelligent dampers which have the characteristics of high-force, rapid-response, low-energy consummation and consequently a promising application future. When the MRFD is applied to the semi-active control, it can significantly enhance the structures'aseismatic performance due to the MRFD's active-adaptation to the external loads. In this dissertation, for the application of MRFDs, a series of numerical simulation researches have been done on the platform of SIMULINK. First of all, in this dissertation, based on the differential equations of bilinear restoring force models and utilization of the powerful and succinct capability of model construction, two kinds of bilinear restoring force models, in which the degradation effects are considered and not considered respectively, have been constructed. The numerical simulation on a three-storey reinforced concrete frame has verified this method of the model construction. Secondly, on the base of the analysis of MRF's performance, various kinds of static and dynamic model have been studied, and their capability of describing the MRFD's virtual performances have been compared. According to the G.Q.Yang experiment's datum, the SIMULINK model of the MRFD based on the modified Bouc-Wen model has been constructed and the numerical simulations about the performance of the MRFD under the sine wave loads have been processed. Finally, two kinds of control algorithms have been studied. Employing the constructed emulational restoring force model and MRFD model, the simulation of the vibration control using MRFD under the seismatic loads has been carried on, and the effect of two control algorithms, the fuzzy control algorithm and the dual-modul control algorithm, has been compared. The different effects which caused by the location of installation of MRFD has been studied as well. Meanwhile aiming at the difficulty of generating the fuzzy control rules, a new practical method has been applied to solve this problem. The study has demonstrated tow facts. The first one is that these two control algorithms are able to mitigate the structure's response under the seismatic loads effectively. Comparatively speaking, the principle of the dual-modul algorithm is simpler, and the algorithm is easier to fulfill with a satisfied control effect. The fuzzy control is relatively complicated, but this algorithm can utilize the capability of MRFD in the whole dynamic range, consequently the control effect is better. The second one is that the MRFD should be installed at the location where the structure is easer to fail or where the effect of the structure under the seismatic loads is more intensive, which can generate more desirable control effect. Generally, the MFRD can significantly reduce the response of the structure under the seismatic load, which makes it become a very promising device compared with various kinds of semi-active control dampers.