High modulus/high strength continuous fibres are used extensively for manufacturing textile preforms, as a reinforcement, for composites due to their excellent specific properties. However, their brittle behaviour and tendency to separate easily into individual filaments or bundles can lead to damages during manufacturing processes such as weaving and braiding. Thus, the critical step in the development of an optimal yarn for textile-reinforced composites is to find an optimum twist, which results in a minimum loss of properties of the composite laminates, while maintaining good processability and sufficient strength for textile and/or composite manufacturing. In this study, twist level has been varied to improve the handling and tensile properties of S-glass yarns (i.e. tensile strength). Varying levels of yarn twist (15–40 twists metre⁻¹) were employed to study its impact on the tensile properties (i.e. tensile strength, modulus, elongation at break etc.). Furthermore, the effect of twist on the tensile properties of non-crimp cross-ply composites produced via vacuum infusion process was studied. It was observed that mechanical performance (i.e. tensile strength properties) of twisted yarns is improved up to 30 twists metre⁻¹ while it is deteriorated at 40 twists metre⁻¹. At yarn level, the experimental results were compared with theoretical estimations utilizing existing models for twisted yarns properties. Discrepancies were observed between experimental and theoretical results especially for high level of twist. The tensile strength and elongation of S-glass cross-ply composites at all levels of twist were higher compared to the composite laminates manufactured by using non-twisted yarns. At composite level, the experimental results were also computed employing rule of mixture and good agreement was observed between experimental and predicted results.

高模量/高强度连续纤维由于其优异的特殊性能而广泛用于制造纺织品预成型件，作为复合材料的增强材料。但是，它们的脆性和容易分离成单独的细丝或束的趋势会导致在制造过程中损坏，例如编织和编织。因此，开发用于织物增强的复合材料的最佳纱线的关键步骤是找到最佳的捻度，从而使复合材料层压板的性能损失降至最低，同时保持良好的可加工性和足够的织物和/或复合材料强度制造业。在这项研究中，已经改变了捻度，以改善S-玻璃纱的处理和拉伸性能（即拉伸强度）。各种纱线捻度（15–40捻度计^-1）用于研究其对拉伸性能的影响（即拉伸强度，模量，断裂伸长率等）。此外，研究了扭曲对通过真空灌注工艺生产的非卷曲交叉复合材料拉伸性能的影响。观察到，加捻纱的机械性能（即抗拉强度性能）在30捻米^-1时得到改善，而在40捻米^-1时却恶化了。。在纱线水平上，使用现有的加捻纱线特性模型，将实验结果与理论估算值进行了比较。实验结果和理论结果之间存在差异，特别是对于高扭曲度。与使用非加捻纱制造的复合材料层压板相比，S-玻璃交叉复合材料在所有加捻水平下的拉伸强度和伸长率都更高。在复合水平上，还使用混合规则来计算实验结果，并且观察到实验结果与预测结果之间的一致性。