Post-impact mechanical characterization of HMPE yarns

Eduarda Da Silva Belloni,Fernanda Mazuco Clain,Carlos Eduardo Marcos Guilherme

doi:10.14311/ap.2021.61.0406

Eduarda Da Silva Belloni, Fernanda Mazuco Clain + Show 1 more

Open Access

https://doi.org/10.14311/ap.2021.61.0406

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Journal: Acta Polytechnica	Publication Date: Jun 30, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Universidade Federal do Rio Grande

Abstract

The present work evaluates the mechanical behaviour of High Modulus Polyethylene (HMPE) yarns after being impacted by sudden axial loads. The influence of loading conditions on the structural integrity of yarns is assessed by tensile, fatigue, and creep tests before and after the impact events. The impact loads were inferred by drop-weight adopting a 300mm height and weights corresponding to 4, 5, and 6% of Yarn Breaking Load (YBL). At 5% YBL, most specimens fail after the impact, and at 6% YBL, all specimens fail. The application of 4% YBL tests results in enhanced creep and fatigue resistances and a decrease in the tensile resistance. Finally, a Scanning Electron Microscopy (SEM) analysis showed that the yarn filaments tend to straighten after the impact, while a decrease in their diameter is noticed due to the longitudinal deformation.

Highlights

Synthetic ropes have been widely used in the oil and gas industry to replace the traditional twisted steel wires, because they offer better flexibility, lower friction coefficient, lighter weight, easier handling, and no potential corrosion-related structural damage
Aiming to contribute to this complex experimental investigation subject, this work analyses the influence of the impact load on the mechanical behaviour of High Module Polyethylene (HMPE) yarns through the performance of tensile, fatigue, and creep tests along with a structural Scanning Electron Microscopy (SEM) analysis
Tensile, fatigue and creep tests were performed with post-impacted specimens, and results were compared with those obtained from the virgin samples

Summary

Introduction

Synthetic ropes have been widely used in the oil and gas industry to replace the traditional twisted steel wires, because they offer better flexibility, lower friction coefficient, lighter weight, easier handling, and no potential corrosion-related structural damage. The most interesting mechanical aspect of this material is its elevated specific strength because of axially oriented long molecule chains This can be attributed to the gel-spinning manufacturing process, in which a solvent disengages the polyethylene molecules among themselves, and the material is subsequently stretched to a high extent culminating in a macromolecular reorientation and improved tenacity and modulus [3]. Similar investigations have shown the mechanical behaviour of the most commonly used synthetic fibres (polyester, polyamide, aramid), assessing creep at low temperatures [10], stiffness [11], and fatigue [12,13,14] of yarns Within this context, Louzada et al [15] showed that the fatigue life of polyester yarns decreases after dynamic loadings, depending on the magnitude of the impact. Aiming to contribute to this complex experimental investigation subject, this work analyses the influence of the impact load on the mechanical behaviour of HMPE yarns through the performance of tensile, fatigue, and creep tests along with a structural SEM analysis

Materials and methods

Yarn breaking load

Tension analysis

Fatigue analysis

Conclusions