An experimental evaluation of S-N curves and validity of Miner´s cumulative damage hypothesis for an ACSR conductor

Laboratory simulation of aeolian vibrations was used in determining the fatigue characteristics of an ACSR conductor subjected to constant and varied amplitude loadings. Using linear regression analyses, S-N curves for first-through fifth-strand breaks were fit to the data, and a pseudoendurance limit of 21.31 MPa (3.09 ksi), was estimated. Subjecting the conductor to three different types of load sequences revealed that M.A. Miner´s cumulative damage hypothesis (1945) is somewhat conservative, but can be assumed valid for design purposes. This information, in conjunction with the actual load histories, will allow electric utility companies to design transmission lines more accurately