Development of acoustic-optical approach for structural health monitoring of composite materails under cyclic loading
The approach for acoustic-optical inspection of mechanical state of composite materials is developing in the presented research. Its examination was performed for cyclic loading conditions of plated specimens made from GFRP laminates. The data obtained by the displacement sensor was compared with those data obtained by the proposed acoustic-optical registration system. Analyzed informative features of acoustic signals (passed along the specimen) include spectrum power, maximum envelope and dispersion of two signal difference value. For the optical images the mean entropy was computed. The paper describes the variation of informative parameters with number of cycles and its analysis based on the emphasis of fatigue fracture stages. This allows estimating current mechanical state of specimens and assessing fatigue life time.