On-specimen strain measurement with fiber optic distributed sensing

The paper explores the possibility of the use of high spatial resolution fiber optic distributed sensing technology for on-specimen strain measurements in laboratory element testing. The approach provides the means to evaluate specimen surface deformation through a novel conjuncture helical envelope configuration of a single optical fiber ribbon. Given that this technology has yet to be applied in the area of material characterization, the paper investigates the most basic setup of a uniaxial compression test. It is shown that the approach provides a full-field view of surface strains with a resolution and accuracy level that is comparable with traditional deformation sensors. It enables the evaluation of small-strain mechanical properties as well as visualization and quantification of any indication of non-uniform test conditions. Because of the relative ease and low-cost for instrumentation, the suggested approach has a great potential to be a routine application for element testing.