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Title: Hybrid steel wire strands with carbon fibre reinforced plastics
Author: Ratner, Alon
ISNI:       0000 0004 5921 8813
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2016
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It has been hypothesised that weight reduction in ropes can be realised by the hybridisation of steel strands with non-metallic carriers in order to improve the efficiency of hoisting processes, most notably in mining applications. While this has been attempted by replacing steel central wires with unreinforced polymers and parallel fibre cores, this investigation has considered the replacement of steel wires with carbon fibre reinforced plastic rods. Fibre reinforced plastics are valued for their high strength-to-weight ratios and ubiquity. Since load sharing is maximal between materials of similar stiffness in a hybrid system, high strength carbon fibres were identified as the most feasible reinforcements for achieving compatible mechanical properties with those of high strength steel wires. A nylon polymer matrix was chosen to provide a reasonable balance between toughness, environmental stability and cost. A pultruder was designed and constructed in order to produce carbon fibre/nylon 12 rods for the creation of novel steel/CFRP hybrid strands. Development of the pultruder highlighted challenges in manufacturing that have been solved for industrial processes but remain underrepresented in academic research. Cost effective and flexible laboratory-scale techniques included fibre spreading by rollers, powder impregnation and the use of heating strips. Superior consolidation of the polymer matrix was obtained in rods pultruded from commingled stretch-broken carbon fibre/nylon tows, which emerged as the most appropriate feedstock. The Young's modulus and tenacity of hybrid carbon fibre/vinyl ester central rods were found to exceed that of standard steel strands, which in turn were higher than that of hybrid strands produced with in-house pultruded rods. Although this identified a need for the refinement of manufacturing conditions, it identified a lower bound of material properties required of the central rod in order to improve the tenacity of a hybrid strand. The finding of higher tenacity for the hybrid carbon fibre/vinyl ester strands demonstrated the feasibility of hybridising steel wire strands with non-metallic rods as a novel means of increasing the strength-to-weight ratio of strands. Finite element modelling of strands with a range of non-metallic core materials confirmed the material selection process by predicting the suitability of carbon fibre reinforced plastics over other core materials in improving the tenacity of hybrid strands.
Supervisor: Pinna, Christophe Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available