Abstracts & Keywords

Trust-region based instantaneous optimal semi-active control of long-
span spatially extended structures with MRF-04K damper

Lin Wei ¹, Li Zhongxian^1,2 and Ding Yang^1,2
1. School of Civil Engineering, Tianjin University, Tianjin 300072, China
2. Tianjin Key Laboratory of Civil Engineering Structures and New Materials, Tianjin 300072, China

Abstract: In the ield of civil engineering, magnetorheological luid (MRF) damper-based semi-active control systems
have received considerable attention for use in protecting structures from natural hazards such as strong earthquakes and
high winds. In this paper, the MRF damper-based semi-active control system is applied to a long-span spatially extended
structure and its feasibility is discussed. Meanwhile, a trust-region method based instantaneous optimal semi-active control
algorithm (TIOC) is proposed to improve the performance of the semi-active control system in a multiple damper situation.
The proposed TIOC describes the control process as a bounded constraint optimization problem, in which an optimal semi-
active control force vector is solved by the trust-region method in every control step to minimize the structural responses. A
numerical example of a railway station roof structure installed with MRF-04K dampers is presented. First, a modiied Bouc-
Wen model is utilized to describe the behavior of the selected MRF-04K damper. Then, two semi-active control systems,
including the well-known clipped-optimal controller and the proposed TIOC controller, are considered. Based on the
characteristics of the long-span spatially extended structure, the performance of the control system is evaluated under uniform
earthquake excitation and travelling-wave excitation with different apparent velocities. The simulation results indicate that
the MR luid damper-based semi-active control systems have the potential to mitigate the responses of full-scale long-span
spatially extended structures under earthquake hazards. The superiority of the proposed TIOC controller is demonstrated by
comparing its control effectiveness with the clipped-optimal controller for several different cases.

Keywords: long-span spatially extended structure; instantaneous optimal control; semi-active control; trust-region
method; magnetorheological (MR) damper; bounded constraint optimization; modiied Bouc-Wen model; clipped-optimal
control