A Dual-Mode Flexible Sensor with Capacitive-Resistive Hybrid Response for Bolt Loosening Monitoring

Area of Science:

• Engineering
• Materials Science
• Sensor Technology

Background:

• Structural health monitoring (SHM) of bolted connections is crucial for engineering system safety.
• Conventional sensors face challenges in balancing detection range and sensitivity for SHM.
• Single-mode sensors have limitations in monitoring preload variations effectively.

Purpose of the Study:

• To develop a flexible sensor overcoming limitations of single-mode sensors for bolted connection monitoring.
• To achieve a seamless transition between capacitive and resistive sensing modes.
• To enable reliable detection of preload variations in bolted connections.

Main Methods:

• Designed a flexible sensor with a hybrid capacitive-resistive sensing mechanism.
• Integrated a hierarchically structured composite layer with tailored material properties.
• Validated sensor performance through experimental testing for cyclic durability and response time.

Main Results:

• The hybrid sensor demonstrated high sensitivity in both low-pressure and high-pressure regions.
• Achieved a seamless transition between sensing modes across different pressure ranges.
• Experimental validation confirmed cyclic durability and rapid response to mechanical changes.

Conclusions:

• The developed flexible sensor shows significant potential for real-time structural health monitoring.
• The hybrid sensing mechanism effectively addresses the limitations of conventional SHM sensors.
• This technology can enhance the safety and reliability of aerospace and industrial systems.