Conference Agenda

This study presents the development and experimental validation of a 3D Finite Element Method (FEM) Digital Twin to analyze the mechanical response of submarine optical fiber cables used for Distributed Acoustic Sensing (DAS). Focusing on the FOCUS infrastructure deployed in the Ionian Sea, the research investigates the strain transfer mechanisms of both Tight Buffered and Loose fiber architectures. The numerical submodels, subjected to kinematic control and Zero-Strain Boundary Conditions, successfully replicate the macroscopic phenomena observed through Swept-Wavelength Interferometry. For the Tight configuration, the Digital Twin accurately reproduces a homogeneous longitu-dinal strain plateau. For the complex Loose configuration, a phenomenological approach utilizing non-linear frictional contact and radial offset was imple-mented to overcome numerical instability. The validated model successfully captures the non-linear shear-lag effect and the highly asymmetrical strain transfer between tension and compression phases, analytically demonstrating the critical role of Excess Fiber Length and micro-buckling in activating Cou-lomb friction. This validated Digital Twin provides a robust baseline for pre-dicting cable performance under complex environmental loads.