Fatigue behaviour of large-diameter wire ropes

Abstract

The factors that influence the tensile fatigue strength of large-diameter wire ropes and the effects of socket materials on wire breakage in sockets were investigated with use of the newly developed wire breakage detecting system. The-fatigue strength of wire ropes was defined at five percent wire breakage rate and had a tendency to increase with an increase in wire tensile strength and diameter and a decrease in self-rotativity, The effect of these factors increases in that order. The size effect was recognized, the larger the rope diameter, the greater the fatigue strength, in case the similar rope construction and the same wire tensile strength were used. These phenomena was explained qualitatively by the fact that wire breakages were observed mostly at points where abrasion had occurred due to contact between wires. The breaking strength of fatigued rope dropped only by three percent when wire breakage rate was eight percent. The epoxy resin proved satisfactory as a socket material.