自适应变刚度TMD的模型试验与数值模拟研究

EXPERIMENTAL AND NUMERICAL STUDY ON ADAPTIVE ADJUSTABLE STIFFNESS TUNED MASS DAMPER

为改善被动调谐质量阻尼器(TMD)对频率调谐敏感及难以改变自身频率的缺陷,提高其对人行桥结构竖向人致振动的控制效果,该文研究了一种自适应变刚度TMD。一个内部开有通孔的TMD质量块被放置在弹簧上,质量块左右两侧各有一根悬臂梁固定在一个步进式推拉杆上。步进式推拉杆可以调节悬臂梁伸入质量块通道中的长度,即改变悬臂梁自由端的长度以改变其刚度,从而实现TMD频率的调谐。主结构附加上TMD后,将对主结构的频谱产生干扰,难以直接识别出主结构的自振频率。因此,该文介绍了自适应变刚度TMD的机械装置,研究了一种基于无阻尼双自由度模型的主结构频率识别算法,接着对其进行了刚度自适应调节和四种人致振动控制的人行桥模型试验,对人行桥模型试验中耦合系统中主结构的频率识别进行了数值模拟。

To improve the sensitivity of passive tuned mass damper(TMD)to frequency tuning,overcome the difficulty of frequency changing,and improve its control effect on vertical human-induced vibration of footbridges,an adaptive variable stiffness TMD is studied in this paper.The mass with an internal through hole is placed on the spring,and a cantilever beam is fixed on each side of the mass,to the left and to the right of a stepping push-pull rod.The stepping push-pull rod can adjust the length of the cantilever beam into the tunnel of the mass,which is the length of the free end,to change its stiffness,thereby realizing the tuning of TMD frequency.After TMD is added to the main structure,the spectrum of the main structure will be disturbed,and it is difficult to directly identify the natural frequency of the main structure.Therefore,this paper first introduces the mechanism of adaptive adjustable stiffness TMD,then proposes a frequency identification algorithm of main structure based on undamped two-degrees-of-freedom model,and then conducts model experiments of a footbridge with stiffness adaptive regulation and four kinds of human-induced vibration control;at last,the decoupled structural frequency identification of the footbridge experiment is simulated.