A novel crack analysis method improves the capabilities of Brillouin scattering-based distributed fiber optic sensing (Brillouin-DFOS) for structural health monitoring. Traditional Brillouin-DFOS systems struggle to detect highly localized strain from sub-millimeter cracks due to their decimeter-scale spatial resolution. The proposed method analyzes the Brillouin scattering spectrum (BSS) derivatives to extract maximum strain near measurement points, enabling precise crack detection and strain quantification. Verified through lab tests and a field experiment on concrete-asphalt pavement, the method accurately tracked crack location, strain variation, and width, showcasing its potential for early detection of structural degradation.
Figure 1. Measurements from BOTDA/R system (a) BSSs along the optical fiber (b) BSS at the position of crack. BOTDA/R: Brillouin optic frequency domain analysis/R; BSS: Brillouin scattering spectrum.
Distributed fiber optic strain sensing for crack detection with Brillouin shift spectrum back analysis
Ruonan Ou, Linqing Luo, Kenichi Soga