A Fiber Bragg Grating Based Torsional Vibration Sensor for Rotating Machinery

Area of Science:

• Optical Engineering
• Mechanical Engineering
• Sensor Technology

Background:

• Torsional vibrations are critical parameters in many mechanical systems.
• Existing sensors often face limitations in size, weight, and environmental interference.
• Fiber Bragg Gratings (FBGs) offer a robust platform for sensing applications.

Purpose of the Study:

• To propose and validate a new fiber Bragg grating (FBG) based sensor for torsional vibration measurement.
• To design a compact, lightweight, and interference-resistant torsional vibration sensor.
• To analyze the sensor's performance characteristics, including natural frequency and sensitivity.

Main Methods:

• Development of a novel sensor architecture utilizing two mass ball optical fiber systems.
• Employing optical fibers as elastomers with mass balls fixed at the center.
• Utilizing wavelength shifts from four FBGs to calculate torsional vibration signals.
• Implementing differential measurement between two systems to mitigate horizontal vibration and temperature interference.
• Conducting numerical analysis and structural parameter design.

Main Results:

• The proposed sensor is small, lightweight, and exhibits anti-electromagnetic interference properties.
• The sensor successfully calculates torsional vibration signals based on FBG wavelength shifts.
• Differential design effectively cancels out horizontal vibration and temperature effects.
• Experimental validation confirmed a minimum torsional natural frequency of 27.35 Hz.
• Achieved a torsional vibration measurement sensitivity of 0.3603 pm/(rad/s²).

Conclusions:

• The developed FBG-based sensor is a viable solution for accurate torsional vibration monitoring.
• The sensor's design offers significant advantages in terms of size, weight, and environmental robustness.
• The achieved sensitivity and frequency response are suitable for various industrial applications.