Design and implementation of a multi-sensor 3D DIC-system for surface monitoring of tubular specimens

The present work outlines the design and implementation of a multi-sensor 3D Digital Image Correlation (DIC) system for surface monitoring of tubular specimens under multiaxial fatigue loading. The system, based on Raspberry Pi computers and implemented in one of the most widely adopted software for DIC, enables high-resolution, full-field displacement and strain measurement across the entire surface of the glass-fiber reinforced specimens onto which it was experimented. This project aims to lay the foundation of a crack detection method, by integrating Digital Image Correlation with Transmitted Light Imaging (TLI) for precise damage localization. A comprehensive system architecture was developed to accommodate eight cameras, paired into four stereoscopic sensors, providing a 360-degree view of the specimen. The performance of the system was thoroughly evaluated through experimentation and benchmarking, assessing its accuracy and conformity to the quality standard of this field. The results demonstrated the effectiveness of the system in capturing detailed surface deformation and providing a robust method for evaluating the integrity of composite materials under complex loading conditions. The proposed system thus lays the foundation for the development of a 360-degree DIC system, offering improved capabilities for monitoring damage in those real-world applications where the ability of full-field assessments is essential.