Compact FBG strain sensor for an accurate measurement method with wide-range temperature compensation

Area of Science:

• Materials Science
• Optical Sensing
• Mechanical Engineering

Background:

• Cross-sensitivity between strain and temperature is a significant challenge in Fiber Bragg Grating (FBG) sensing.
• Adhesive thermal expansion mismatch can amplify temperature effects in packaged FBG strain sensors.

Purpose of the Study:

• To develop a specially designed FBG strain sensor with wide-range temperature compensation.
• To address the issue of magnified temperature effects in packaged FBG strain sensors.

Main Methods:

• Fabrication of a compact FBG strain sensor (18 mm length, 0.35 g weight).
• Experimental testing to determine strain and temperature sensitivities.
• Post-compensation analysis to evaluate measurement accuracy.

Main Results:

• The sensor exhibits a strain sensitivity of 1.35 pm/με with high linearity (R² = 0.99951).
• Demonstrated temperature sensitivity of 29.8 pm/℃ over a -50 °C to 150 °C range (R² = 0.9979).
• Achieved strain measurement accuracy exceeding 99% after temperature interference elimination.

Conclusions:

• The developed FBG strain sensor effectively compensates for temperature variations.
• This sensor enables real-time thermal compensation for applications like wing load monitoring.
• Enhanced structural safety is achieved through accurate strain measurements in dynamic environments.