Analysis and design of active tuned mass damper systems.

摘要

Although a number of passive/active tuned mass dampers have been installed and used on tall buildings, bridges and towers, a number of important problems related to their analysis design remain to be resolved. They include system optimization, choice of active control strategy, effects of stroke limits on system design and practical constraints such as space and power limitations.; The purpose of this dissertation is to address some of these theoretic and practical questions, and to provide a practical design guideline for passive/active and hybrid tuned mass damper systems.; First, a set of optimization formulas is proposed to determine optimal parameters of passive tuned mass damper (TMD) subjected to several ground or wind excitations considering the effect of modal participation factors. The formulas provide not only the optimal parameters for the TMD design under the excitations considered but also the good estimates or initial values for other excitations. Based on these methods, simplified formulas are proposed to transfer the TMD design into the conventional Single-degree-of-freedom design. The present methods are also applied to multi-degree-of-freedom structures with single or multi-mass damper systems.; Second, the active tuned mass damper (ATMD) performance principle is outlined and compared with existing active control algorithms for self-supported structure/ATMD systems. The comparison shows that nonlinear control strategies are effective for active tuned mass dampers, while the LQR control law among the present methods can be effective. The state-velocity feedback based on the LQR control law is shown to be effective in reducing wind induced acceleration response, while the state feedback is better to reduce earthquake induced displacement response.; Following this analysis, two active control strategies are proposed to deal with harmonic excitations or random excitations, based on linear feedback control. Based on the latter method, the equivalent damping induced by an ATMD can be obtained. Therefore, the simplified method of ATMD design is proposed.; The application of an active tuned mass damper (ATMD) to reduce the wind-induced response of an existing 340m-high communication tower located in Nanjing (China) is discussed under the design seismic or wind excitations. The feasibility analysis for passive/active control device is carried out. Several control strategies and three kinds of feedback control laws (state feedback, state velocity feedback and complete feedback) are discussed. The conclusion obtained is that the active tuned mass damper can meet not only the comfort requirements for the whole tower under the strong wind (average wind speed 20.7 m/sec, 50 year recurrence) but also the safety requirements under severe earthquakes and strong wind excitations. The active tuned mass damper design is proposed next under severe constrains, such as space limit, friction resistance, rotations caused by ATMD, the effect of stroke limit and force limit. The final design of active mass damper (AMD){dollar}sp1{dollar} is presented which meets all the constrains.; Finally, a practical design procedure for ATMD is proposed based on the present methods and other powerful conventional active control algorithms. A set of programs to deal with the design procedure is outlined. ftn{dollar}sp1{dollar} The active mass damper is one of three categories of active tuned mass damper.