A Comprehensive Study on Measurement Accuracy of Distributed Fiber Optic Sensors Embedded within Capillaries of Solid...

Area of Science:

• Materials Science
• Mechanical Engineering
• Sensor Technology

Background:

• Embedding fiber optic sensors (FOSs) in structures is vital for structural health monitoring (SHM).
• Capillary-based embedding offers a novel approach for integrating FOSs into solid parts.
• Understanding factors affecting strain measurement accuracy is essential for reliable SHM.

Purpose of the Study:

• To propose and investigate a novel method for embedding FOSs using capillaries.
• To analyze the influence of fiber position and orientation uncertainties within capillaries on strain measurement accuracy.
• To determine the optimal capillary size for accurate strain measurements.

Main Methods:

• Development of analytical and numerical models to predict strain distributions.
• Experimental validation using Aluminum 6082 specimens with embedded FOSs in capillaries of varying diameters (2mm, 4mm, 6mm).
• In situ strain measurement during four-point bending tests, followed by post-test cross-section analysis to determine actual fiber positions.

Main Results:

• Fiber position relative to the capillary center is the primary factor influencing strain measurement accuracy.
• Fiber orientation variations within the capillary showed a negligible impact on accuracy.
• Increasing capillary diameter from 2mm to 6mm increased measurement error from 10.5% to 18.5%.

Conclusions:

• A 2mm capillary diameter offers the lowest measurement error and ease of embedding for FOSs.
• The study provides insights into optimizing FOS embedding for accurate strain monitoring.
• Measured strain falling within a defined strain window suggests potential for future crack detection applications.