Damage quantification in fiber reinforced polymer composites using a hybrid non-destructive testing approach

Damage is an inherently dynamic and multi-scale process. Of interest herein is the progressive identification of tensile and fatigue failure mechanisms activated in newly developed glass fiber reinforced polymer composites (GFRCs). To achieve this goal, the potential of data fusion in structural damage detection, identification and remaining-life estimation is investigated by integrating heterogeneous monitoring techniques and extracting information suitable for validated data-driven modeling. Damage monitoring is achieved by the use of a novel hybrid Non-Destructive Testing (NDT) system, relying on the combination of Digital Image Correlation (DIC), Acoustic Emission (AE), and Infrared Thermography (IRT) which are three emerging and powerful NDT techniques. DIC and IRT full-field strain and temperature maps reveal progressive development of structural hot spots, associated with locations in which inelastic strains accumulate and damage initiates. The combination of DIC and mechanical data further quantifies hysteretic fatigue behavior, due to: i) stiffness degradation, ii) increase in energy dissipation, and iii) exponential growth in the longitudinal and transversal strain due to damage accumulation as the number of fatigue samples increase. In addition, extracted features from the recorded AE signals indicate three characteristic stages of fatigue life that can be used to construct a framework for reliable fatigue remaining life-predictions.M.S., Mechanical Engineering -- Drexel University, 201