The Research On Intelligent Base-isolation Based On MR Damper

The basic isolation technique is one of the efficient ways to withstand and resist the effect of an earthquake. By putting an isolation layer between the basis and the upper structure, it can reduce the transfer of the earthquake energy to the upper structure, so, the upper structure and the internal establishment could be protected efficiently in strong shocks. However, one problem with the normal isolation technique is that it enlarges the drift of the isolation layer when it reduces the response of the main structure to the earthquake, especially near the epicenter, the large velocity of the impulse which is the character of the ground motion will engender a larger drift for the isolation layer.The blend controlling algorithm was developed to solve this problem, that is, adding the semi-active or passive control component to the normal basic isolation system , then ,using the modern controlling theory to control the response of the structure simultaneously. The results show that application of blend isolation can improve not only the applicability of basic isolation system but also the isolation effect. Magnetorhelogical (MR) fluid dampers, one of the semi-active control devices, have been developed recently. It is the most promising device because of its low power requirement.In this paper, the structure design theory of MR dampers is investigated. The main contents are included as follows:(1) The methods of damping force calculating in the different work pattern are deduced. On the basis of the theoretical model, the relationship between the dynamic performance and the structure parameters is analyzed as well.(2) The basic design principle of MR dampers is systemically studied, and with Maxwell, an electromagnetic analysis software, a simulink analysis of a finite element model is conducted. Some approaches to improve the electromagnetism performance are gained.(3) Based on some experiments, the characteristics of the damping force, the response time and the energy dissipation of MR dampers are investigated. A new three-layer frame model was designed in this work. Five types structures were simulated, that is, the original structure, the ordinary basic isolation, attached with MR dampers under passive-off, passive-on and semi-active controlling, respectively. The results show that: the performance of MR intellectual base-isolation system which is a safe and practical device, is better than that of passive isolation device. The controlling effect under intelligent controlling algorism is better than that of the Passive-off, Passive-on and Passive isolation control algorithm.