Understanding the three-dimensional variability of unidirectional composites is relevant to the material performance and the development of advanced material modelling strategies. This work proposes a new methodology for the characterisation of unidirectional composites, showcased on carbon fibre/poly(ether-ether-ketone) tapes. Three microstructural descriptors were here introduced, each representing an increasing level of complexity in the fibre architecture: from a tortuosity-based single fibre trajectory analysis to fibre groups’ behaviour, to fibre network interconnectivity. The methodology was developed and validated on real material datasets acquired via X-ray computed tomography. A facile method for image analysis was used to reconstruct the three-dimensional fibrous architecture at a single fibre path resolution. The approach bridges a gap in the traditional approach and nomenclature typical of the composite field to describe and quantify complex fibre organization in unidirectional composites, highlighting micro- and mesoscopic features, such as edge-core effects in the fibre arrangement, possibly occurring in tow spreading. The study of the parameter interdependence showed relationships, which will provide further insight for future research in the study of microstructure formation of unidirectional composites, its evolution during processing or loading, and input for advanced modelling techniques based on Representative Volume Elements.

了解单向复合材料的三维可变性与材料性能和先进材料建模策略的开发有关。这项工作提出了一种表征单向复合材料的新方法，展示在碳纤维/聚（醚-醚-酮）胶带上。这里介绍了三个微观结构描述符，每个描述符都代表了光纤架构中日益复杂的水平：从基于弯曲度的单光纤轨迹分析到光纤组的行为，再到光纤网络互连。该方法是在通过 X 射线计算机断层扫描获得的真实材料数据集上开发和验证的。一种简便的图像分析方法用于以单纤维路径分辨率重建三维纤维结构。该方法弥补了复合材料领域典型的传统方法和命名法的空白，以描述和量化单向复合材料中复杂的纤维组织，突出微观和介观特征，例如纤维排列中的边缘-芯效应，可能发生在丝束展开中. 参数相互依赖性的研究表明了相关性，这将为未来研究单向复合材料的微观结构形成、加工或加载过程中的演变以及基于代表性体积元素的高级建模技术的输入提供进一步的见解。例如光纤排列中的边芯效应，可能发生在丝束展开中。参数相互依赖性的研究表明了相关性，这将为未来研究单向复合材料的微观结构形成、加工或加载过程中的演变以及基于代表性体积元素的高级建模技术的输入提供进一步的见解。例如光纤排列中的边芯效应，可能发生在丝束展开中。参数相互依赖性的研究表明了相关性，这将为未来研究单向复合材料的微观结构形成、加工或加载过程中的演变以及基于代表性体积元素的高级建模技术的输入提供进一步的见解。