Dissimilar Materials Assembled and Integrated FBG Vibration Sensor With Structural Thermal Strain Self-Compensation

A fiber Bragg grating (FBG) vibration sensor with structural thermal strain self-compensation was proposed in this article. It used cartwheel flexible hinges as an elastomer. Based on the theoretical model of the sensor established by derivation, the genetic algorithm was used to achieve the globally optimized structure sizes under multiple constraints, while the modal simulation analysis was carried out to verify the results. The shrink fitting method was used to complete the assembly and integration between parts made of dissimilar materials. The experimental results show that the natural frequency of the vibration sensor is 324 Hz, and it has a good working condition in the frequency range of 5160 Hz. The vibration sensitivity of the sensor at 40 Hz frequency is 198.46 pm/g, with lateral cross interference of less than 2%, and the temperature sensitivity is −2.64 pm/°C. The FBG vibration sensor can satisfy the requirements of mechanical equipment fault diagnosis, and has a good application prospect in the vibration signal detection of mechanical equipment with complex and large range of temperature changes in the working environment of oil and gas pipelines, industrial motors, aeroengines and so on.