Prediction of rope bending fatigue life based on wire breaking rate

Abstract

Steel wire ropes offer manufacturer-independent safety performance, while the durability performance can be different. To assess the damage status of a wire rope during its service, fail-safe methods are used, so it is necessary to know the progression of the damage to apply them. This paper proposes an analytical method for estimating the fatigue life of steel wire ropes. Using a dimensionless analysis, the characteristic damage curve of each rope category has been suggested, setting the basis of a predictive maintenance procedure extendable to all areas of rope application where bending fatigue is the first discard criterion for rope replacement. Rotary bending fatigue tests are performed on different rope construction specimens, and the evolution of broken wires is monitored. It has been demonstrated that the trend of breakage level is exponential with time, regardless of the type of rope and the stress level imposed.