Dynamic modelling and control of shear-mode rotational MR damper for mitigating hazard vibration of building structures

Magneto-rheological (MR) materials and their devices are being rapidly developed and have drawn surge of interest for the potential application in vibration control. Among them, a novel shear-mode rotational MR damper (SM-RMRD) with adaptive variable stiffness and damping was developed for adaptive structural control in real-time against different types of earthquakes. To make use of this innovative device perfectly, a robust and reliable model should be developed to simulate the nonlinear and hysteretic behaviours for the application in adaptive control. Accordingly, this research initially presents a new phenomenological model to describe the force response of the SM-RMRD. Then, model parameters are estimated based on experimental data of force, displacement and velocity, which were directly or indirectly obtained from the device under different loading protocols. The field dependence of each model parameter is also investigated so that a general model with current-related parameters is acquired for designing the control strategy. Using the current-dependent model of SM-RMRD, a semi-active controller is developed and implemented to the SM-RMRD to produce the feedback control for the structures in real-time. Finally, the effectiveness of proposed control method is appraised by a numerical study, in which an SM-RMRDs-incorporated three-storey building model with different control strategies are subjected to various scaled benchmark earthquakes. The comparison result verifies the excellent capacity of the proposed controller based on the developed phenomenological model in terms of reducing the storey acceleration and inter-storey drift.