New sensing solutions based on fibre Bragg gratings for engineering applications

The article introduces new sensing solutions utilising Fibre Bragg Gratings (FBGs) for civil engineering and geotechnical applications. The first, named EpsilonPeak, is an innovative FBG design developed to measure non-uniform strain fields, such as those found in textile composites, cracked concrete, or steel after reaching the yield point (plastic strains). This sensor is resistant to shearing strains, significantly extending its measurement range compared to conventional FBGs. The second solution is a hybrid sensor that combines the benefits of spot FBGs with distributed fibre optic sensing (DFOS). The sensor's composite, monolithic core contains two optical fibres: one with a predefined FBG array for automated readings using relatively inexpensive interrogators, and the other, a standard telecom fibre, providing data periodically but continuously along its length. The article summarises the design and potential applications of both sensing solutions.