FEASIBILITY STUDY ON AN OPTICAL STRAIN GAGE BASED ON FLUORESCENCE RESPONSE OF GRAPHENE QUANTUM DOTS

In this study, based on the excellent fluorescence properties of graphene quantum dots (GQDs) and their good response to mechanical effects, the GQDs were mixed with epoxy resin to make a coating sensor. Taking this as the research object, the film was coated on the Q235 tensile steel sample, which can dynamically monitor the stress and strain of the steel sample. By investigating the effects of the concentration of the GQDs solution, the synchronization of the film and the steel component, and the residual stress of the epoxy resin, the mechanism of the visual fluorescence signal was analyzed. The response of stress-strain of steel sample and the fluorescence intensity of coating sensor under uniaxial tension and cyclic loading were studied. The test results showed that the synthesized coating sensor had good stability and can produce very sensitive fluorescence response to the stress and strain. The fluorescence intensity of the coating sensor increased with the increase of stress and strain, and decreased with the decrease of stress and strain under cyclic loading, which had the potential to act as a new optical strain gauge. Based on the test results, the stress and strain of the GQDs-epoxy resin composites coated on tensile steel samples with different thicknesses were studied by numerical simulation.