摆式碰撞双重调谐质量阻尼器减振性能研究

柔性高耸桥塔具有刚度低、阻尼小等特点，极易在强风以及地震等动力荷载下产生大幅振动。摆式调谐质量阻尼器(Pendulum Tuned Mass Damper，简称摆式TMD)是目前常用的高耸结构被动控制方法，但其具有参数敏感、控制频域窄、阻尼实现手段复杂等突出缺点。为此，提出了一种摆式碰撞双重调谐质量阻尼器(Pendulum Pounding Double Tuned Mass Damper，简称PPDTMD)，该阻尼器具有双重调频能力，既提高了其减振性能，也解决了传统摆式TMD需要外接阻尼元件和碰撞式TMD噪声问题。建立了多自由度结构与摆式碰撞双重调谐质量阻尼器耦合系统的运动方程，通过参数搜索方法确定了其最优设计参数，拟合得到简化设计公式，对比了PPDTMD与传统摆式TMD的减振效果。以某自立桥塔为研究对象，分别研究了在涡振、地震、强风荷载作用下PPDTMD的抑振性能。研究结果表明:PPDTMD具有双重调谐特性，减振性能显著提升，当质量比为4%时，PPDTMD相对于理想摆式TMD、实际摆式TMD的动力放大系数峰值分别下降了11%和46%;在PPDTMD控制下，自立桥塔涡激共振(简谐激励)作用下的塔顶位移响应幅值减振率为71.9%；Kobe波作用下的塔顶位移峰值及均方值减振率分别为34.7%和60.2%；抖振力作用下的塔顶位移峰值及均方值减振率分别为26.9%和43.5%;不同动力荷载下PPDTMD的减振性能均优于传统摆式TMD。

Control Performance of Pendulum Pounding Double Tuned Mass Damper Under Various Excitations

High-risen flexible bridge tower is prone to large-amplitude vibrations under various dynamic loads due to low damping and stiffness, and it may rises several function and safety issues. Conventional tuned mass damper (TMD) is one of the most common methods to vibration control of high-risen structures. However, problems as the poor robustness, the narrow control frequency domain and complicated damping realization method restricts its applications in engineering practices. In this paper, a pendulum pounding double tuned mass damper (PPDTMD) is proposed for vibration control of flexible tower with low damping. PPDTMD employ poundings from rolling balls and viscoelastic materials layer inside the pendulum mass for energy dissipation, which is more convenient for damping realization.The motion equations of a multiple degree of freedom structure coupled with a PPDTMD is derived. Based on the numerical optimization program, the optimal parameters for PPDTMD is obtained and summarized in the form of simplified formulas. The control performance and robustness of PPDTMD and the conventional pendulum TMD is compared. A bridge tower is utilized to validate the effectiveness of PPDTMD under various excitations. The results indicate that the proposed damper is a double tuned device which can dramatically increase the control performance. The dynamic magnification factor with PPDTMD is reduced 11% and 46%, respectively compared to that with the idealized TMD and realized TMD. With PPDTMD control, the vortex-induced vibration amplitude (harmonic excitation) of the bridge tower is reduced to 71.9%. The peak and RMS response reduction under Kobe wave are 34.7% and 60.2% respectively, and that under buffeting loading are 26.9% and 43.5% respectively. The control performance of PPDTMD outperform that of the conventional TMD even under different dynamic excitations.