Scalable Tracking and Validation of Individual Fibre Trajectories and Diameters in Unidirectional Carbon Fibre Composites

Realistic fibre trajectories are essential for micromechanical models to study the influence of fibre architecture variations on the performance of composite materials. This work presents a scalable micro-CT based fibre trajectorytracking method capable of tracking individual fibre trajectories and their diameters across the full scanned volume.The method tracks continuous fibre paths, their corresponding diameters, and quantifies geometric parameters including orientation distributions, diameter statistics, and diameter variation along the fibre length. The workflow isevaluated on low-contrast, high fibre volume fraction (> 60%) micro-CT dataset of unidirectional carbon fibre reinforced polymer composites. The extracted geometric parameters show consistent trends with experimental diametermeasurements and structure-tensor-based orientation estimates, demonstrating the reliability of the approach. Theextracted fibre trajectories offer detailed geometric information that can be utilised in micromechanical studies andprovide a basis for comprehensive characterisation of unidirectional composite microstructures.