Time History Modeling of Vibrations on Overhead Conductors With Variable Bending Stiffness

Although bending stiffness of cables is small, it has a large influence on the deformed shape near constraints. A practical application where it is important is for the prediction of the deflection curve of transmission-line conductors during aeolian vibrations. These vortex-induced vibrations may cause fretting fatigue failure at or near the location of clamped devices. The objective of this paper is to model with a nonlinear time history finite-element analysis the deformed shape of conductors during aeolian vibrations using available bending stiffness models. The deformed shape obtained numerically is compared to laboratory measurements available in the literature. It was found that theoretical bending stiffness models can be used to predict the deformed shape of cables near the clamps. However, the results obtained with variable bending stiffness are not significantly more accurate than those for a constant bending stiffness equal to half of the maximum theoretical bending stiffness. In general, the variation of bending stiffness found experimentally is less important than the prediction of nonlinear models. The dynamic nonlinear numerical method presented here remains a powerful tool for the prediction of the deformed shape of vibrating conductors.