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Điều khiển kết cấu - Chương 4

Tuned mass damper systems Một van điều tiết khối lượng điều chỉnh (TMD) là một thiết bị bao gồm một khối lượng, mùa xuân, và một van điều tiết được gắn vào một cấu trúc để giảm các phản ứng năng động của cấu trúc. Tần số của van điều tiết được điều chỉnh để một cấu trúc cụ thể tần số để khi tần số đó là kích thích, thông gió sẽ cộng hưởng của giai đoạn với sự chuyển động cấu trúc. Năng lượng là tiêu tan bởi lực quán tính giảm chấn tác động lên cấu trúc | 259 Chapter 4 Tuned mass damper systems 4.1 Introduction A tuned mass damper TMD is a device consisting of a mass a spring and a damper that is attached to a structure in order to reduce the dynamic response of the structure. The frequency of the damper is tuned to a particular structural frequency so that when that frequency is excited the damper will resonate out of phase with the structural motion. Energy is dissipated by the damper inertia force acting on the structure. The TMD concept was first applied by Frahm in 1909 Frahm 1909 to reduce the rolling motion of ships as well as ship hull vibrations. A theory for the TMD was presented later in the paper by Ormondroyd Den Hartog 1928 followed by a detailed discussion of optimal tuning and damping parameters in Den Hartog s book on Mechanical Vibrations 1940 . The initial theory was applicable for an undamped SDOF system subjected to a sinusoidal force excitation. Extension of the theory to damped SDOF systems has been investigated by numerous researchers. Significant contributions were made by Randall et al. 1981 Warburton 1980 1981 1982 and Tsai Lin 1993 . This chapter starts with an introductory example of a TMD design and a brief description of some of the implementations of tuned mass dampers in building structures. A rigorous theory of tuned mass dampers for SDOF systems subjected to harmonic force excitation and harmonic ground motion is discussed next. Various cases including an undamped TMD attached to an undamped 260 Chapter 4 Tuned Mass Damper Systems SDOF system a damped TMD attached to an undamped SDOF system and a damped TMD attached to a damped SDOF system are considered. Time history responses for a range of SDOF systems connected to optimally tuned TMD and subjected to harmonic and seismic excitations are presented. The theory is then extended to MDOF systems where the TMD is used to dampen out the vibrations of a specific mode. An assessment of the optimal placement locations of TMDs in building