Faculty of Civil Engineering of Tabriz University, Tabriz, Iran
10.24200/j30.2025.65523.3381
Abstract
Magnetorheological (MR) dampers demonstrate intelligent behavior when subjected to a magnetic field, with their structural response controlled by adjusting the magnetic field's intensity. Various control algorithms and laws have been proposed to implement these control systems. Among the fundamental control laws for semi-active systems, the Skyhook and Groundhook control laws are particularly notable. A hybrid approach combining both of them can be employed to enhance the performance of these control laws. However, determining the optimal contribution of each control law—Skyhook and Groundhook—within the hybrid control law presents a significant challenge. In this study, an eight-story structure equipped with MR dampers is analyzed under the excitation of three earthquakes, Bam, Loma-Prieta, and Northridge, to evaluate the effectiveness of the proposed hybrid control law. The objective is to optimize the hybrid control law using the pattern search algorithm. The hybrid control law for structures with MR dampers can be implemented in two ways: on-off and continuous. In the on-off method, the voltage applied to the MR dampers is restricted to two extreme values, whereas the continuous method allows for voltage adjustment across the entire range between these boundaries. Through an analysis of both on-off and continuous hybrid control laws, it is evident that their performance in reducing the structure's displacement, velocity, and acceleration responses is nearly identical. However, the continuous hybrid control law achieves comparable efficiency with significantly lower control forces. As a result, the continuous optimal hybrid control law emerges as a simple yet highly effective solution. Furthermore, by assuming the same weight of force and displacement in the cost function, it is shown that the participation percentage of the Skyhook control law in the hybrid control law is much higher than that of the Groundhook control law. The optimal participation rate of the Skyhook law is obtained to be approximately 0.95.
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Ghaffarzadeh,H , Safikhanlou,S and Aran,A . (2026). The Optimal Hybrid Controller Based on Ground Acceleration for a Structure Equipped with MR Dampers. Sharif Journal of Civil Engineering, 42(1), 3-16. doi: 10.24200/j30.2025.65523.3381
MLA
Ghaffarzadeh,H , , Safikhanlou,S , and Aran,A . "The Optimal Hybrid Controller Based on Ground Acceleration for a Structure Equipped with MR Dampers", Sharif Journal of Civil Engineering, 42, 1, 2026, 3-16. doi: 10.24200/j30.2025.65523.3381
HARVARD
Ghaffarzadeh H, Safikhanlou S, Aran A. (2026). 'The Optimal Hybrid Controller Based on Ground Acceleration for a Structure Equipped with MR Dampers', Sharif Journal of Civil Engineering, 42(1), pp. 3-16. doi: 10.24200/j30.2025.65523.3381
CHICAGO
H Ghaffarzadeh, S Safikhanlou and A Aran, "The Optimal Hybrid Controller Based on Ground Acceleration for a Structure Equipped with MR Dampers," Sharif Journal of Civil Engineering, 42 1 (2026): 3-16, doi: 10.24200/j30.2025.65523.3381
VANCOUVER
Ghaffarzadeh H, Safikhanlou S, Aran A. The Optimal Hybrid Controller Based on Ground Acceleration for a Structure Equipped with MR Dampers. Sharif Journal of Civil Engineering. 2026;42(1):3-16 (In Persian). doi: 10.24200/j30.2025.65523.3381
