An empirical model to predict the lifetime of braided HMPE handling ropes under cyclic bend over sheave (CBOS) loading

Abstract

a b s t r a c tRepeated bending over sheaves is one of the main causes of failure of synthetic fibre ropes used in marine operations. There are few published results available and even fewer models allowing lifetime to be estimated. A large new set of data from cyclic bend over sheave (CBOS) tests on 250 kN break load braided HMPE synthetic ropes is presented first, both tests to failure and interrupted tests followed by residual strength measurements. These data are analysed in order to propose an empirical lifetime model. This is identified using constant load tests, then evaluated for variable load sequences. A methodology to include rope lifetime prediction in handling system design is then discussed.

Condition Monitoring Technologies for Synthetic Fiber Ropes - a Review

“…It is important to know that each of the different damage mechanisms have an effect on the other damage mechanisms. For CBOS loading in particular, Davies, François, Lacotte, Vu, and Durville (2015) identify four distinct mechanisms through observation of damages:…”

“…Abrasion within the rope 4. Fiber breakage Davies et al (2015) emphasize that these mechanisms are not acting independently, but act together, making failure analysis more complex. This also means that monitoring one parameter alone might not be sufficient to obtain a good condition monitoring system for fiber ropes.…”

Tension fatigue failure prediction for HMPE fibre ropes

“…Fatigue investigations on HMPE have been mainly focused on rope bending fatigue performance (e.g. [20]- [24]) as it was identified as the most severe case for handling lines. Nevertheless to be able to quantify the life time expectancy of a rope we have to establish a theory for pure tension fatigue.…”

The effect of rope termination on the performance of polyester mooring ropes for marine applications

“…They cannot transfer bending moments or transverse forces of any magnitude and are unstable under compressive loads, they will bend out (Lee et al, 2015). Over the last few decades, many successful structural models have been developed to predict the static tensile behaviour of ropes and its failure mechanism (Davies et al, 2015). These models often assume that spatial locations along individual strands can be described by a helix with a sinusoidal undulation in their radius direction.…”