Optimization of Rope Sheave Groove Profile to Improve Synthetic Rope Lifetime

Abstract

The aim of this thesis is to determine whether an optimized rope sheave groove profile can improve the lifetime of a synthetic rope. Synthetic ropes have begun to see use in hoisting applications as they offer multiple benefits. Over the course of its lifetime a hoist’s rope will be replaced several times due to wear, it is important to maximise the lifetime of the rope to provide the greatest efficiency for the hoist, to improve environmental sustainability and most importantly to provide the greatest safety. The rope sheaves of a hoist represent a good opportunity to improve the rope lifetime as they are one of the main points of interaction between the load and the rope. Due to the difference in properties and behaviour between a synthetic rope and a steel rope, analysis needs to be carried out to assess whether the groove profile of the rope sheaves can be updated to optimize the rope lifetime.

This work begins with a study of the interaction between the rope and the rope sheave from the wider knowledge base of steel ropes, as well as investigation into existing standards, patents and guidance related to the use of synthetic ropes in hoisting applications. Based upon this research several test pieces were selected and subjected to cyclic bending over sheave (CBOS) testing.

The results of the testing show a small variation in rope life between different sheave designs and that the rope sheave groove profile does effect rope lifetime. Through further testing and refinement of the groove profile design more significant improvements could be achieved.