Intelligent Bi-State Control for the Structure with Magnetorheological Dampers

Magnetorheological (MR) damper is a kind of intelligent control device, which can be used to reduce earthquake responses of building structures. In this paper, a mathematical model of MR dampers is introduced, and the relation between the yielding shear stress and the control current of MR dampers is formulated. Then the bi-state control strategy of the structure with MR dampers is studied. Results show that the control strategy easily leads to overrun of the parameters and the control force of MR dampers under the minor earthquake, which results in amplification of acceleration responses of the structure. For this reason, a modified bi-state control strategy is proposed. In this method, the neural network technique is used to predict the seismic responses of the structure, whilst the intelligent bi-state control strategy on the smart structure with MR dampers is applied to solve the time-delay problem of semiactive control. Numerical simulation of a three-story reinforced concrete frame structure with MR dampers and without MR dampers are performed using the bi-state control method, the modified bi-state control method and the intelligent bi-state control method. Results show that the intelligent control strategy solves the time-delay problem of semiactive control and overrun of control forces under the minor earthquake, and the control force is most veritable and the earthquake mitigation effect is the best.