Miss. LIN, JUI CHI

Ph.D. candidate

National Taiwan University

This research focuses on the development of advanced fiber Bragg grating (FBG) sensing
systems for high-fidelity structural and thermo-mechanical characterization. The first study
establishes an integrated experimental approach that combines a multi-segment FBG array with
the Conjugate Beam Method (CBM) and frequency analysis to reconstruct the static and
dynamic responses of cantilever beams. Distributed strain data are transformed into

displacement fields, achieving a reconstruction error below 2% understatic loading. Frequency-
domain analysis further validates the system’s capability to identify modal content up to 14

kHz, demonstrating strong agreement with finite-element predictions and confirming the
suitability of the FBG–CBM approach for compact, scalable structural health monitoring.
Building upon these foundations, a second study introduces a frequency–temperature
regression and inverse-estimation methodology to determine temperature-dependent material
properties using FBG-derived modal frequencies. Linear regression models quantify the
thermal sensitivity of vibration modes, while the Nelder–Mead simplex algorithm inversely
estimates the temperature-dependent Young’s modulus and density for aluminum plates. This
enables non-destructive, frequency-only material characterization across coupled thermal–
dynamic environments.
Together, these works demonstrate a unified optical sensing system capable of resolving
strain, displacement, and material-property variations through wavelength interrogation. The
results highlight the potential of FBG sensing for next-generation smart diagnostics, providing
precise, multi-modal insights into the thermo-mechanical behavior of structural components
relevant to engineering, aerospace, energy, and advanced manufacturing applications.