Numerical fatigue life estimation of aluminium 6201-T81 wires containing geometric discontinuities.

Abstract

Previous works have shown that fretting fatigue can be modelled as a notch problem due to the mild superficial damage produced in the partial slip regime during fretting. In this context, the aim of this numerical and experimental study is to estimate the fatigue life of aluminium 6201-T81 wires, used in overhead conductors, containing geometric discontinuities. These discontinuities induce a stress field analogous to the fretting problem. To perform the fatigue life assessments the LM-Nf relationship, which is an extension of the Theory of Critical Distance (TCD), was applied. The LM-Nf relationship was calibrated using two S-N curves, one of a plain wire and other of a notched wire. The validation of the numerical approach estimations was performed using a wire containing a through hole. The estimations were fallen almost entirely among factor 3 bands when compared with the experimental results. This factor 3 represents the biggest scatter in the S-N curves used to calibrate the LM-Nf relation. The TCD approach applied, in terms of point method, provide accurate life estimations in the range 105 and 106 cycles.