Corrosion effects on the fatigue performance of high-strength bolted friction connections

In this paper, the corrosion effects on the fatigue performance of the friction connections are experimentally and numerically investigated. Fatigue test was conducted on the connections with four corrosion levels, and the failure mode and fracture surfaces were analyzed. Based on the finite element modeling of the connection, the crack initiation life caused by the fretting fatigue was calculated based on several multiaxial fatigue criteria, and the crack propagation life in the complex stress field was predicted using the AFGROW software. The results show that the fatigue life of the friction connections could be significantly reduced by corrosion, and the fatigue failure occurred near the minimum cross-section plane of the inner plates. It was also observed that the fatigue cracks initiated at the fretting wear scar and the corrosion pits at the hole edge for the uncorroded and corroded connections, respectively. The predictions show that the fatigue life prediction method in which the crack initiation and propagation lives are both considered can accurately predict the fatigue behavior of the uncorroded connections under different stress ranges. The fatigue life of the corroded friction connections with a mass loss ratio>7.8% can be estimated by assuming an initial crack at the hole edge in the minimum cross-section plane and ignoring the crack initiation life induced by fretting damage.