Full-Field Dynamic Parameters and Tension Identification of Stayed Cables Using a Novel Holographic Vision-Based...

Area of Science:

• Structural Engineering
• Optical Measurement Techniques
• Vibration Analysis

Background:

• Existing vision-based methods struggle with slender stayed cables due to low-amplitude vibrations, limiting accurate identification of higher-order dynamic parameters.
• Accurate monitoring of cable-supported structures is crucial for safety and maintenance.

Purpose of the Study:

• To propose a novel holographic vision-based method for accurate identification of high-order full-field dynamic parameters and tension estimation in stayed cables.
• To develop a non-contact, visual, and quantifiable strategy for monitoring cable-supported structures.

Main Methods:

• A full-field optical flow tracking algorithm was developed to capture dynamic displacement information from holographic feature points.
• Frequency-domain analysis was used to extract natural frequencies and damping ratios.
• An Eulerian-based amplification algorithm (holographic feature point video magnification - HFPVM) was employed to enhance weak motion signals.

Main Results:

• The holographic vision-based method accurately identified the first five natural frequencies with errors below 5%.
• Cable tension estimation showed a maximum deviation of 6.86%.
• The first three normalized holographic mode shapes and dynamic displacement vectors were identified with a Modal Assurance Criterion (MAC) value up to 99.51%.

Conclusions:

• The proposed non-contact holographic vision-based method provides a convenient and low-cost solution for stayed cable tension estimation.
• This method offers a comprehensive, visual, and quantifiable strategy for periodic or long-term monitoring of cable-supported structures, demonstrating significant practical potential.