Low-Frequency Structural Vibration Monitoring Using a Hetero-Core Fiber Optic Accelerometer

This paper investigates the dynamic monitoring performance and applicability of a hetero-core optical fiber accelerometer for low-frequency vibration monitoring and modal analysis. The accelerometer is fabricated with optical fiber, offering advantages such as immunity to electromagnetic induction and minimal impact from temperature variations. Consequently, it is considered applicable for structural health monitoring in outdoor environments. An experiment was conducted to perform dynamic monitoring and modal analysis on a cantilever beam structure with low natural frequencies. The optical fiber accelerometer was mounted on the beam, and an impulse hammer was employed to induce excitation. The accelerometer consisted of a semicircular-shaped hetero-core optical fiber with an additional mass of 7.0 x 10–⁵ kg. It was demonstrated that the proposed hetero-core optical fiber accelerometer can measure the vibration of the structural beam with sufficient accuracy to estimate the first and second mode characteristics.