Offshore oil exploration in deeper waters has necessitated the development of lighter mooring systems to replace traditional steel cable and chain platforms. This study focuses on evaluating the mechanical behavior and fatigue degradation mechanism of high modulus polyethylene (HMPE) fibers in yarn-on-yarn abrasion tests. Initial characterization tests, including linear density, rupture force, and thermal analysis, were conducted on HMPE yarns. Yarn-on-yarn abrasion tests were performed under dry, wet, and salty conditions, with varying loads, while statistical analysis examined the influence of environmental factors and load levels on yarn performance. Scanning electron microscopy (SEM) analysis provided insights into material degradation mechanisms. Results showed superior performance in freshwater-immersed yarns due to cooling and lubrication effects, while dry conditions led to material melting. SEM analysis revealed critical degradation zones, particularly in interwoven regions, where increased friction and heat concentration caused material fusion. Degradation evolution mechanisms highlighted fatigue-induced rupture of yarns, knot formation, and material melting near failure points. This comprehensive analysis enhances understanding of HMPE yarn performance and degradation in offshore mooring applications, laying the groundwork for developing advanced mooring systems capable of withstanding deep-sea environments.

Polyester fibers are the most used in the manufacture of ropes for mooring systems and offshore operation, thus being constantly subjected to different situations. Such requests are implicated in a variety of load conditions, and their effects must be studied. This work presents data referring to an experimental study on the behavior of the quasi-static and dynamic stiffness of polyester yarns considering different mechanical levels of degradation and use. The study is performed with five different types of multifilament samples, these were extracted from a virgin spool and sub-ropes tested for tension and fatigue. The experimental procedure is carried out through an initial characterization where the linear density, the Yarn Break Load - YBL and the linear tenacity of the samples are determined. Continuing with the experimental tests, a procedure standardized by ISO 18962-2 is then carried out, consisting of three quasi-static stages and three dynamic stages, where the data acquired in the tests allow the determination of a dimensionless stiffness value. The results showed an increase in the quasi-static stiffness, tending to a plateau, and a linear increase in the dynamic stiffness, but with somewhat similar behavior between the samples. The results related to the total quasi-static stiffness also show that the specimens extracted from sub-ropes that underwent fatigue present greater total non-dimensionalized stiffness, this is indicative of the mechanical fatigue procedure as an improvement of the specimens, giving them greater stiffness, and consequently greater stresses rupture, a behavior that should be explored in future studies.