Vortex-Induced Vibration and Countermeasure of a Tubular Transmission Tower

Abstract

Transmission towers with steel tubes or so-called tubular towers are widely used for ultra-high voltage (UHV) transmission because of their overall higher strength and stability, and better wind resistant capability. However, within a specific wind velocity range, tubular members with a high slenderness ratio are susceptible to joint fatigue failure under the vortex-induced vibration (VIV). To thoroughly unveil the mechanism of VIV of tubular members in UHV transmission towers, this paper first measures the acceleration and corresponding wind velocity of a tubular member under the VIV, followed by an identification of the first-order frequency. Then, a simulation framework for the tubular members subjected to the VIV is proposed. The system considered is simplified as a mass–spring–damping system with the non-linear coupling effect between the tubular member and wind field taken into account. Based on the analysis, the lock-in region and maximum displacement amplitudes in the cross-wind direction are calculated, while the simulation accuracy is verified via comparison with the on-site measured data. Meanwhile, the influence of damping ratio on the VIV is studied. Finally, a new type of radial spoiler is proposed to suppress the VIV of the tubular members. The results of the 3D simulation show that the proposed radial spoiler can effectively suppress the vortex generation, and there is no noticeable vibration after the installation of the countermeasure. In effect, it was demonstrated that the proposed countermeasure can effectively suppress the VIV of the tubular tower. The parametric analysis reveals that the distance between two adjacent spoilers has a significant impact on the control efficiency and should be carefully designed for each project.

Experimental Study on Corrosion of Galfan‐Coated Full‐Locked Coil Ropes in a Natatorium Environment

“…After the air conditioner is closed in summer, the indoor temperature rises, and the cable is in a high temperature, high humidity, and high chloride environment; when the air conditioner is turned on in winter, the cable is easy to condense, and the cable is in high humidity and high chlorine environment [11]. e corrosion problem is relatively prominent in the natatorium environment compared with other structures [12]. Galfancoated full-locked coil ropes (starting now referred to as cable) are commonly used in engineering and are in a highstress state during service.…”