Wind-Induced Vibration Response and Weak Locations of 110 kV Diverging Branch Rods Under Strong Wind

[Objective] The cross arms of the diverging branch rods are arranged perpendicularly, with cross-sectional dimensions varying linearly with height. Due to the complexity of structural modeling, corresponding structural analysis has not yet been conducted. [Method] To analyze the wind-induced vibration response and weak locations of diverging branch rods under strong wind conditions, a shell element finite element model was established to obtain its true mode shapes and a simplified beam element finite element model was proposed. Non-structural components were also addressed. The validity of the simplified model is verified by comparing mode shapes and frequencies. Dynamic response analysis under wind attack angles of 90°, 60°, 45°, and 0° were conducted to study the wind-induced vibration response and identify weak locations at various angles. [Result] The study shows that the mode shapes of diverging branch rods are primarily characterized by bending deformation, with negligible influence from torsion. Under a 90° wind reaction angle, the maximum wind-induced displacement at the top of the tower exceeds the relevant specified limits, and the stress at the base of the tower is the highest. Under a 45° wind reaction angle, the displacement at the top of the tower is the smallest, but the stress at the base is second only to that under a 90° wind reaction angle. The 90° wind reaction angle represents the most adverse condition. [Conclusion] The design control parameter for diverging branch rods is the displacement at the top of the tower. Additionally, the stress at the base of the tower is significant and poses a risk. Under different wind attack angles at a design wind speed of 29 m/s, the stability of the diverging branch rods meets the requirements, but the displacement at the top of the tower exceeds the limits. Existing diverging branch rods should be reinforced, while planned constructions can consider reducing span length or increasing cross-sectional area to avoid displacement exceeding limits.