| Large flue gas desulfurization towers are self-supporting tall thin-walled structures with high flexibility and low damping.Under fluctuating wind loads,severe along-wind buffeting and across-wind vortex-induced resonance at specific wind speeds may occur.The change of cross section of desulfurization tower weakens the transverse stiffness of the structure and makes the wind-induced dynamic response characteristics of the structure more complicated.However,the calculation of wind load and wind-induced response of the structure with variable section is still rough in Chinese current code(GB 50009-2012).The classical tuned mass damper(TMD)has been widely used in wind vibration control of such tall structures,there are still some limitations such as narrow frequency modulation range and heavy dependence on the quality of the damper.Therefore,it is of great scientific significance and engineering application value to study wind-induced vibration characteristics and lightweight vibration reduction control system of high-rise structures with variable section.In this paper,a high-rise desulfurization tower is taken as the research object.Through finite element with ANSYS simulation and numerical simulation with MATLAB,the wind-induced dynamic response characteristics in along-wind direction and across-wind direction of a cylindrical structure with variable section are analyzed.Combined with Chinese current codes,the differences and reliability of the common calculation methods of equivalent static wind load for cylindrical structures with variable section are compared.Tuned mass inerter system(TMIS)was introduced to study the wind-vibration control of tall desulphurization tower,and parameter optimization methods of the dampers was established for wind-vibration response control of the tower.Three new dampers were proposed based on TMIS and TMD,and the influence of different connection modes of inerter system and classical TMD on the control effect of dampers was analyzed,and the energy dissipation mechanism of TMIS was revealed.The main conclusions of this paper are as follows:(1)The wind-vibration response analysis in frequency domain scheme of desulfurization tower based on pseudo-excitation method is reliable,and the obtained frequency domain response results are consistent with the time domain results.The along-wind response of the tower is dominated by the first mode,and the pulsation response under dynamic wind load is obviously greater than the average response under static wind load.The equivalent static wind load of the Inertia Wind Load can be used to evaluate the wind-vibration response of the tall desulfurization tower in a relatively simple way and ensuring the accuracy of calculation results.(2)The along-wind vibration effect of the desulfurization tower is significant,and the vortex-induced vibration of the first mode of the superstructure should be taken into account.There are limitations in calculating the transverse wind load of the tall desulphurization tower with variable section in the domestic load codes.There is some error between the calculation results and the response analysis in the time domain and frequency domain.In this study,the analysis route of downwind and along-wind vibration effect of desulfurization tower and the research results of equivalent static wind load obtained by comparing various calculation methods can provide engineering reference and basis for refined wind effect analysis of high-rise structures with variable section.(3)The optimization design method of TMIS based on genetic algorithm has strong applicability.TMIS has better control effect on the wind-induced vibration of desulfurization tower downwind and transverse wind and stronger tuning robustness than the classical TMD.Through the inerter subsystem paralleled with the tuned spring,the smaller damping coefficient increases the dynamic response of the mass block of the damper,while the inerter component amplifies the apparent mass of the damper,thus realizing more energy dissipation on the main structure and reflecting the lightweight vibration reduction effect. |
