ABSTRACT
The diagnosis of steel structures, especially their performance under plastic deformations beyond the yield point, presents significant challenges for conventional measurement techniques. Extremely high strain ranges, nonlinear effects, and shearing forces are among the reasons why direct surface measurements are difficult. This article presents three fibre optic sensing solutions designed for the diagnostics of metal structures: (1) the Plastic Deformation Sensor (PDS) for detecting the onset of yielding; (2) EpsilonPeak, based on Fibre Bragg Gratings (FBG), for measuring non-uniform plastic strains; and (3) Distributed Fibre Optic Sensors (DFOS) for continuous strain sensing along the entire analysed length. Both laboratory studies and practical applications are discussed in this context.
