A unified analytical model for the self-damping of stranded cables under aeolian vibrations

Abstract

This work presents a new formulation for the self-damping of overhead conductors subjected to aeolian vibrations. Differently from the empirical models, customarily employed in engineering applications, the proposed formulation is based on a mechanical description of the hysteretic bending behaviour of the strands, which is obtained in the paper starting from a description of the strand internal structure. A unified non-dimensional expression for the dissipated energy of ACSR cables is proposed, this is a novel expression that allows to express in closed-form the cable self-damping as a power law. Differently from empirical power laws which are used to express energy dissipation of overhead conductors, and usually require experimental tests to define their coefficients, the proposed formulation is dimensionally homogeneous; it leads to a meaningful proportionality coefficient; it leads to values of the exponents well within the ranges of the empirical values from the literature; it possibly allows to reduce the need for expensive laboratory tests. This new damping model is applied to the study of the aeolian vibrations of a full-scale experimental test-span. The results highlight the paramount role played by the cable self-damping, and compare favorably with the predictions stemming from both empirical power laws and available experimental data.