Residual Properties of the Drawn Steel Wires for Damage-Based Fretting Fatigue Models of the Wire Ropes

Abstract

This paper presents the residual properties and parameters of the damage-based fatigue life prediction models of the steel wire ropes under fretting fatigue conditions. The damage mechanics-based approach is employed to develop the predictive method for the reliability of the steel wire ropes. The elastic modulus is dependent on the fatigue load condition and the accumulated number of the load cycles. The characteristic degradation of the Young’s modulus of drawn steel wires is established through the phenomenological presentation of the interrupted fatigue test data. The samples are given a quasi-static loading followed by a block cyclic loading with various stress amplitudes and ratios. The residual Young’s modulus is calculated after each block of cycles. The effect of the different loading condition with the amplitude and mean stress on the measured fatigue life of a single wire is presented using the life parameter, χ. The residual Young’s modulus data are presented in terms of normalized quantities. Significant reduction in the elastic modulus due to fatigue is exhibited after enduring 70% of the fatigue life of the material. The fitting constants are obtained, and the fitted equation is used to describe the degradation of Young’s modulus at N number of cycles. Subsequently, the data can be applied to predict the fatigue-life of steel wire ropes and assess its reliability through fretting-induced damage models.