Design and Development of an Optical Vibration Sensor Based on Fiber Bragg Grating (FBG) Technology for Aerospace Applications

Vibration analysis involves studying mechanical oscillations in systems caused by factors such as imbalances, misalignments, external forces, or internal dynamics. These oscillations may be periodic, random, or transient, and understanding their frequency and amplitude is essential for diagnosing mechanical issues, ensuring system stability, and optimizing performance. A key tool in vibration analysis is Fourier analysis, which enables the decomposition of complex vibration signals into their constituent frequency components. By transforming time-domain data into the frequency domain using the Fourier Transform, dominant frequencies, harmonics, and resonances can be more clearly identified. This method is particularly useful for detecting periodic disturbances or resonances within a system and is critical for applications such as condition monitoring, predictive maintenance, and system design optimization, where understanding vibration frequency content is vital for performance and reliability assessments. Leveraging the versatility of Fiber Bragg Grating (FBG) sensors, a carefully designed "comb structure"comprising teeth of varying lengths, each embedding an FBG sensor - can be constructed to mechanically approximate the frequency decomposition achieved through Fourier analysis. This structure functions similarly to a comb, with each blade tuned to a distinct resonant frequency, thereby isolating different frequency components based on the vibration response of each blade. Since achieving different resonant frequencies can be accomplished by simply scaling the geometry of a well-designed blade, this paper will focus on analyzing the design and results of the blade with the lowest resonant frequency.