Análise numérica e modelagem computacional de um sistema estrutural com controle semiativo de vibração do tipo amortecedor magnetorreológico

Abstract

Structural vibration control systems are means of protection which aim the reduction of excessive or undesirable vibrations caused by dynamic loads on civil structures in other to assure safety and comfort criteria. Those systems are classified into passive, active, hybrid and semi-active. Semi-active controls systems are among the most used due to reliability and simplicity reasons. The magnetorheological dampers (MR) are semi-active devices capable of changing from liquid to semisolid state in milliseconds, in a reversible manner, when exposed to a magnetic field. Due to this capability, MR dampers are considered as a perfect tool for controlling structural systems - allowing the management of damping load fast and safely, with small amount of energy. This work studies the efficiency of semi-active control systems, by means of MR dampers applied to a two-story building model subject to accelerations applied to its basis. The obtained results are compared to data available in the literature, showing good agreement. The adopted methodology consists in evaluating the MR dampers behavior in three distinct situations: 1) applied as a passive damper: under constant voltage, with no variation of dampers properties; 2) applied as a semiactive controller for which the activation voltage is determined by the clipped optimal algorithm based on a linear quadratic regulator - with voltages of 0V or a maximum value; 3) applied as a semiactive controller with optimized activation voltage, assuming voltage values ranging from 0V to a maximum value. This strategy is original and consists in the main contribution of the present work. For comparison purposes, the studied model was also subjected to purely active control, by assuming a mechanical actuator exerting control forces directly on the structure. This strategy allows confronting the performance of the MR damper with an active controller.