Experimental device for fretting fatigue tests in 6201 aluminum alloy wires from overhead conductors

Abstract – This article presents the design, production and testing of an experimental device that seeks to evaluate fretting fatigue of wires taken from conductors used in energy transmission lines. The fretting device has three independent actuators that allow tests to be carried out under controlled load (or displacement). Thus, the effect of relevant parameters to the fretting fatigue process (such as normal, tangential and bulk forces, wear level, and wear surface morphology) can be studied. To evaluate the device performance, tests were carried out on 6201 aluminum alloy wires, considering two different contact normal forces, P. Results showed that, for lives greater than 106 cycles, the increase of P from 250 to 500 N produced a substantial reduction on fatigue strength when compared to tests of smooth wire specimens. The SEM images and EDS analyses after the fretting fatigue test demonstrate that the wire-wire marks generated by the device show all the characteristics found in wires of internal layers of overhead conductors fractured by fatigue under fretting conditions.