High temperature strain sensor based on a fiber Bragg grating and rhombus metal structure

Area of Science:

• Materials Science
• Optical Sensors
• Mechanical Engineering

Background:

• Fiber Bragg Gratings (FBGs) are widely used for sensing applications.
• High-temperature strain sensing remains a challenge due to material limitations and sensor degradation.
• Existing sensors often lack controllable sensitivity and high-temperature stability.

Purpose of the Study:

• To develop and demonstrate a novel high-temperature strain sensor.
• To investigate the strain sensing performance of the proposed sensor at elevated temperatures.
• To achieve controllable and enhanced strain sensitivity.

Main Methods:

• Fabrication of a sensor using a polyimide-coated fiber Bragg grating (FBG) integrated into a rhombus metal structure.
• Utilizing low softening point glass for fixing the FBG within the structure.
• Experimental validation using an equi-intensity cantilever beam and a high-temperature chamber up to 300°C.

Main Results:

• The sensor successfully operated at temperatures up to 300°C.
• A strain resolution of approximately 10 με was achieved.
• The average wavelength strain sensitivity at 300°C was measured as 1.821 pm/με (compression) and 1.814 pm/με (tension).
• Strain sensitivity was demonstrated to be controllable by adjusting the rhombus structure dimensions.

Conclusions:

• The proposed polyimide-coated FBG sensor with a rhombus structure is effective for high-temperature strain measurement.
• The sensor exhibits controllable and enhanced strain sensitivity.
• This technology offers a promising solution for strain monitoring in high-temperature environments.