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Evaluation of Bending Deformations in Slender Cylindrical Structures Using Distributed Optical Fibre Strain Sensing
Madhubhashitha Herath1,2, Oleg V Ivanov1,2, Kaushal Bhavsar1,2
1School of Engineering and Technology, Faculty of Science and Engineering, University of Hull, Hull HU6 7RX, UK.
Sensors (Basel, Switzerland)
|December 11, 2025
Summary
Optical fibre sensing effectively monitors bending in cylindrical structures like subsea power cables. This technology can determine the type, magnitude, and orientation of deformations, enhancing infrastructure safety.
Area of Science:
- Structural Health Monitoring
- Optical Sensing Technologies
- Mechanical Engineering
Background:
- Slender cylindrical structures, such as subsea power cables, are vital infrastructure components.
- These structures are susceptible to bending deformation, which can lead to failure.
- Effective monitoring of bending is crucial for ensuring structural integrity.
Purpose of the Study:
- To investigate the application of distributed optical fibre sensors for monitoring bending deformation in slender cylindrical structures.
- To analyze the strain responses of optical fibres in different configurations under various bending conditions.
- To develop a method for reconstructing deformed shapes using optical fibre sensing data.
Main Methods:
- Utilized Brillouin optical time-domain reflectometry (BOTDR) for strain sensing.
- Experimentally tested a 6m circular hollow section (CHS) under three-point and constant curvature bending.
- Attached optical fibres longitudinally and helically to the CHS surface.
- Developed a finite element model (FEM) for simulation and interpretation.
- Performed inverse analysis on strain data to reconstruct deformed shapes.
Main Results:
- Distinct strain profiles were observed for longitudinally and helically wound fibres, differentiating bending types.
- The study successfully differentiated between three-point bending and constant curvature bending behaviours.
- Optical fibre sensing demonstrated the capability to evaluate the type, magnitude, and orientation of bending deformations.
- FEM simulations aided in interpreting experimental strain responses.
Conclusions:
- Distributed optical fibre sensing is a viable method for monitoring bending in cylindrical structures.
- The configuration of optical fibres significantly influences the detected strain profiles.
- This research provides fundamental insights for designing effective sensing systems for critical cylindrical infrastructure.
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