Experimental Study of the Fatigue Performance of Overhead Pure Aluminium Cables

Abstract This work presents an experimental comparative study to evaluate the fatigue performance of two overhead cables made of different types of pure aluminium. A battery of eighteen fatigue tests was carried out on two cables, named Orchid and AAAC 1120 823 MCM, made of pure aluminium, i.e. AA 1350 and AA 1120, respectively. Fatigue of cables is a main cause of failure resulting from aeolian vibration. Through wind, the cable is subjected to three types of loading which are the clamping force, the bending stress and the mean stress due to the cable stretching load. This stretching load is expressed in term of H/w parameter which is the ratio between the horizontal stretching load H and the linear weight of the cable w. The CIGRE organization has suggested the use of the H/w as a parameter of power line cable design against fatigue due to aeolian vibration. Fatigue tests were conducted for cable/suspension clamp systems and two S-N curves were generated at the same H/w value of 1820 m. One curve was obtained for each cable. The generated S-N curves proved that the AA 1120 cable could sustain a higher number of cycles before fatigue failure than the AA 1350 for the considered value of H/w. Additionally, a failure map was raised to determine the morphology of wire break. The microscopic analysis showed that the cracks were nucleated in the fretted marks. Data presented in this study will be helpful for the fatigue design of overhead cables against aeolian vibration.