A semi-active control algorithm for nonlinear structures based on uniform distribution of deformation theory

Abstract

Semi-active control is a promising method for vibration control of civil structures. Magneto-rheological (MR) damper is one of the most common and practical devices among other semi-active control devices. The command voltage is the only controllable property of an MR damper. There are several algorithms for determining the MR damper command voltage such as active control-based algorithms. On active-based algorithms, an initial reference control force is achieved based on a reference active control algorithm, then this force converts to applied voltage. Uniform Distribution of Deformations (UDD) theory is a concept which intends to use the maximum capacity of elemental and structural ductility. When deformations are uniform throughout the entire structure, damages are mostly uniform and the maximum of damage is reduced. This point can be used for designing a new active-based semi-active algorithm. The innovative Uniform Deformation Control (UDC) is an active-based control algorithm. Reference active control forces are achieved using a massless Virtual Added frame with Pinned connections (VAP). This virtual frame makes deformation of the structure more uniform. The axial forces of the VAP beams are the reference active control forces. Afterward, based on these forces, the command voltages of semi-active MR damper are determined. The VAP characteristics are optimized using Charged System Search (CSS) optimization method for making the structural deformations more uniform. Therefore, this new innovative proposed algorithm focuses on reducing damages contrary to common algorithms which focus on reducing responses. The contribution of the present paper is to introduce the new damage-based algorithm. Then, this algorithm will be investigated in comparison with two other common algorithms. The effectiveness of the new proposed algorithm is proved via nonlinear numerical investigations on an office building. The new algorithm can reduce displacements and accelerations with relatively low control forces while making deformations more uniform.