自适应TMD减振性能试验

为改善目前工程中应用的调谐质量阻尼器(tuned mass damper,简称TMD)对频率敏感和频率难以调节的缺点,提出了一种自适应TMD,由可变质量块、弹簧、伺服控制系统、驱动系统和阻尼器组成。其中,伺服控制系统由一个加速度传感器和一块单片机电路板组成。在环境激励下,单片机电路板接收位于主结构上的加速度传感器传来的信号,利用短时傅里叶变换识别得到主结构的第1阶自振频率,并自发启动驱动装置改变TMD的质量,以调节TMD的频率与识别得到的主结构频率一致。通过人行桥模型试验验证了自适应TMD的可行性、可靠性和有效性。试验结果表明,自适应TMD能准确识别模型结构的竖向一阶自振频率,并通过调节质量重新调谐自身频率,与识别得到的频率相同。自由衰减振动试验和受迫振动试验表明,与启动调节前的失调TMD相比,启动调节后的谐调TMD能够提高模型结构的等效阻尼比,降低其加速度响应峰值和均方根值。

An Adaptive-Passive Tuned Mass Damper System

Tuned mass damper (TMD) in the engineering application is sensitive to a frequency which is difficult to adjust. In light of this problem, this paper proposes an adaptive-passive TMD. It includes, besides the damper, the variable mass, spring, servo control system, and driving system. The servo control system consists of an acceleration sensor and a single chip computer circuit board which is used to receive the structural acceleration sensor signals under ambient excitation. The short-time Fourier transform (STFT) is used to identify the first order natural frequency of the structure and adaptively change the quality of the TMD to adjust the frequency of TMD and recognize the frequency of the main structure. The feasibility, reliability, and validity of the adaptive-passive TMD are verified by the pedestrian bridge model test. The experimental results show that the adaptive-passive TMD can accurately identify the vertical vibration frequency of the model structure and retune its frequency to the same frequency. Freedom vibration tests and forced vibration tests show that compared with the mistuned TMD, the retuned TMD can improve the equivalent damping ratio of the pedestrian model, and reduce the peak acceleration response and root-mean-square (RMS) values.