Corrosion influence on lifetime prediction to determine the Wöhler curves of outer layer strand of a steel wire rope

Abstract

Wire ropes play important roles in industry development, maritime industrial services and civil engineering applications. They are composed of multi-wire strands twisted together to form a structure with enormous mechanical properties, combining high axial strength, rigidity and torsional flexibility. In most applications, wire ropes are exposed to different damage mechanisms. One of these mechanisms is corrosion, which can accelerate the damage to cable components and lead to brutal and unforeseen failure. In this regard, experimental tensile tests were carried out on several strand samples; one sample was virgin and the others were corroded by immersion of a well-defined number of strands in sulfuric acid solutions. The studied strands were extracted from a 19 * 7 non-rotating steel wire rope. The static damage enables to monitor the evolution of residual stresses of damaged samples with different corrosion levels. Based on the ultimate residual stress and the endurance limit of the virgin strand, the influence of corrosion on the strand‘s endurance limit was studied by plotting the S-N curves according to the unified theory. The obtained results enabled to assess the mechanical behavior of the strand in a corrosive environment under static stress and to predict the number of cycles at which the strand will break. This procedure makes it possible to anticipate the service life of this structure under corrosive conditions. It also helps to establish a solid maintenance system that ensures a safe and reliable working environment.