SMA-MR Damper And Vibration Control In Long-Span Canopy Roof Structures

ABSTRACT In the field of vibration control for civil structures, intelligent control based onself-perceptive, self-diagnosis and self-adaptive properties of smart material hasattracted much attention by researchers, in which Shape Memory Alloy (SMA) andMagnetorheological Fluid (MR) are two kinds of most promising materials in theresearch . In this thesis, a composite SMA-MR damper is proposed and designed utilizingSMA and MR material properties. The control performance of the damper isinvestigated. And the vibration control theory and control effectiveness of the damperin long-span canopy roof structures are studied. Through the research, followingcreative achievements have been made:(1)　A composite SMA-MR damper is proposed and designed. Based on the superelastic and shape memory property of the SMA material and the feature of MR fluid, a composite SMA-MR damper having the capacity of semi-active control is developed.(2)　A theoretical modal of SMA-MR damper is established and the damper's working performance is analyzed. By inputting sine waves, the hysteresis curves are obtained under both small and large earthquakes. And parameter analysis of the SMA-MR damper is carried out.(3)　The damping performance of the SMA-MR damper is systematically investigated. A numerical simulation analysis for a single-degree-of-freedom system is performed. It is shown that the SMA-MR damper possesses a significant performance of damping, and the adaptive smart control for large and small earthquakes is realized.(4)　The designed SMA-MR damper is applied to long-span canopy roof structures to investigate its vibration control performance. Theoretical modal of the system is set up and a computer program for vibration control is developed. Then, the control performance is analyzed with inputting three-dimensional El-Centro earthquake waves in small, medium and large seismic intensity.北京工业大学工学硕士学位论文(5)　Parametric studies for control performance of the SMA-MR damper in long-span canopy roof structures is carried out. By analysis, practical engineering suggestions are presented.