DAMAGE EVALUATION IN GLASS-CERAMIC MATRIX COMPOSITES VIA COMBINED INFRARED THERMOGRAPHY AND ACOUSTIC EMISSION

Infrared thermography (IRT) and acoustic emission (AE) were combined to assess damage initiation and evolution in SiC-fiber reinforced barium osumilite (barium-magnesium-aluminium-silicate, BMAS) glass-ceramic matrix composites under static and fatigue loads. IRT proved powerful in monitoring crack propagation under both types of loadings as well as in identifying the critical damage mechanisms leading to ultimate fracture. IRT also enabled early prediction of the composite's residual life, as early as at 73% of the duration of the final loading cycle. A novel lock-in IRT methodology that overcomes the limitations of the Wohler's curve approach is also proposed herein for the rapid and accurate assessment of the fatigue limit of CMCs by using information from as few tests as on one single specimen. AE enabled real-time monitoring of the fracture behavior with energy- and frequency-related descriptors proving able to discern instances of high stress. AE results were successfully benchmarked across IRT heat dissipation results.