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One of the challenges in the field of civil engineering is to mitigate the seismic vibration of structures induced by dynamic loads, such as earthquake and strong wind in order to prevent undesirable damages causing human discomfort and economic consequence. The vibration control systems can be categorized as passive, active and semi-active. In recent years, semi-active control systems demonstrate better control effects than both passive and active systems. Semi-active control devices can behave as passive devices in the event of a power loss, and are therefore more reliable and consume less power than the active systems. In this study, to evaluate the effectiveness of the semi-active tuned mass damper using MR damper and a fuzzy logic controller, the nonlinear model of the nine-story benchmark structure is subjected to earthquake excitation. The semi-active tuned mass damper consists of a 1000 kN magnetorheological damper and the damping force of the MR damper is controlled by the fuzzy logic controller.The Bouc–Wen model is utilized to model the dynamic behavior of the MR damper. For this purpose, the increment dynamic analysis (IDA) is conducted to consider the effectiveness of the maximum acceleration of two near- and far-field acceleration records on the performance of the control systems. Two near-field earthquake acceleration records including Kobe (1995) and Northridge (1994) and two far-field earthquake acceleration records including El Centro (1940) and Hachinohe (1968) are used in this study. To achieve the optimum parameters of tuned mass damper, a numerical search method is used to reduce the displacement of the last floor of the structure. The optimal mass ratio, damping and the frequency of the tuned mass damper of these analysis for this structure are 3.5 %, 10 % and 2 rad/s. Also, this benchmark structure is modeled in OpenSees and the fuzzy inference system was implemented in MATLAB. In order to implement the semi-active control system, it’s necessary to communicate between OpenSees and MATLAB. For this purpose TCP-IP method is used. The displacement and velocity response of the ninth floor of structure equipped with tunned mass damper are considered as the input values for the fuzzy inference system. Furthermore, the required voltage of MR damper in this floor is defined as the output parameter of the fuzzy system. Moreover, the membership functions of fuzzy control are triangle and trapezoidal functions. The obtained results of the FLC are compared with the those of passive controlled structure. Therefore, absolute displacement and acceleration values of the last floor of the structure, the maximum relative displacement and the base shear values are investigate. The results showed that the FLC reduces the maximum last floor displacement, the maximum relative displacement and the maximum base shear by 17.75 %, 15.88 % and 16.85 % as compared to the uncontrolled structure, respectively and also, it reduces those responses by 3.62 %, 1.17 % and 15.76 % as compared to the passive response, respectively. Furtheremore, the fuzzy control system has effective performance than the passive system to decrease the maximum and residual displacement of the stories. On the other hand, the fuzzy control system has a low performance in reducing the maximum last floor acceleration.

Keywords: Semi-active control, MR-STMD, Tuned mass damper, MR damper, Fuzzy logic controller.

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