Mechanical behavior and failure prediction of corroded central wires in a steel lifting cable: experimental and probabilistic approach

In this work, a stringent experimental procedure was developed to accelerate the corrosion of central wires extracted from 19×7 lifting cables so that it should take about a few tens of hours to reproduce several months of service-induced degradation. To an accuracy of 100 mm, the specimens were carefully cut, marked and immersed in a 30% sulfuric acid solution in laboratory maintaining conditions. At scheduled intervals (up to a 40-hour total immersion time), selected samples were taken out of the solution, gently washed, and tested monotonically to failure to measure their residual ultimate force. The tests showed a pronounced,asymptotically approaching decrease in mechanical efficiency with increasing length of exposure. Further analysis of the force-versus-immersion data, using nonlinear regression tools, provided an explicit relationship between the normalized residual strength and the life fraction β, defined as the ratio of the immersion time to the total test duration. In this static environment, the damage curve is divided by using Erismann’s damage law into three different damage regimes: a beginning degradation phase of slow, incipient damage; and intermediate stage of rapidly developing, critical degradation; and a final abrupt degradation zone. To further define the variability of material degradation, a probabilistic damage–reliability model built on a Weibull distribution linked the computed life fraction and the survival probability of any specific stress level. This hybrid methodology – integrating accelerated corrosion protocols with advanced statistical and analytical modelling – provides a strong predictive tool for determining the remaining life of the CWs and facilitates the introduction of focused condition-based maintenance policies.