Thermal failure mechanism of fiber ropes when bent over sheaves

Thermal damage is an important failure mechanism that affects the bending failure of fiber ropes. This is relevant because synthetic fibers often have a relatively low melting point and low thermal conductivity. In cyclic bending over sheave (CBOS), the heat generated by friction and deformation is not conducted rapidly to the external environment, and the temperature of the rope core increases quickly. This higher temperature greatly reduces the mechanical properties of the fiber, thus accelerating the final rope failure. In this paper, evidence of thermal damage in the bending process of a braided synthetic fiber rope is given. The test conditions inducing thermal damage are discussed, including stress level, bending frequency and diameter ratio. The reasons for the heat generation and the dynamic process of heat accumulation inside the rope during CBOS are also discussed. This study aims to provide theoretical and experimental guidance for the design and use of fiber rope.