Condition assessment and severity grading of non-metallic armoured optical-electrical cables in marine winch systems based on three-dimensional geometric measurements

Reliable condition assessment of non-metallic armoured optical-electrical cables is critical for the operational safety of marine winch systems. Unlike metallic wire ropes, these lightweight composite cables are more susceptible to surface degradation, yet their complex damage morphology remains difficult to quantify objectively using conventional visual inspection. This study presents a geometry-driven framework that transforms three-dimensional point cloud measurements into quantitative damage characterization and maintenance-oriented severity grading. The framework integrates vibration stabilization, cylindrical unfolding, and topology-constrained localization to extract damage regions. A multi-indicator geometric scheme, combining depth, uplift, area, width, and volume, comprehensively describes damage morphology. A severity grading strategy grounded in outer sheath thickness criteria links quantitative measurements to practical maintenance decision-making. Under limited training data and irregular damage morphology conditions, the proposed method achieves an IoU of 0.9233 ± 0.0872 across 1200 annotated samples, outperforming both threshold-based baselines and deep learning models. The ablation study confirms the essential roles of vibration stabilization and topology constraint. The resulting condition indicators can support objective health monitoring and condition-based maintenance of non-metallic armoured optical-electrical cables in marine winch systems.