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. © 2022 Xi'an Highway University. All rights reserved.