Monitoring of Indentation Damage Propagation and Residual Strength Estimation in Iron Filler-Loaded Glass/Epoxy Composites using Acoustic Emission

The main challenges of using fiberglass composites are poor impact resistance and understanding of damage mechanisms during loading. This work focuses on improving the indentation resistance of glass/epoxy composites by the incorporation of industrial waste iron fillers with maximum concentration of 50 µm in size. Moreover, the quasi-static indentation test with acoustic emission (AE) monitoring was employed to study the damage initiation and propagation of baseline and optimized 10 wt.% of filler-loaded composites. Post-indentation performance was evaluated by conducting compression after indentation test. The result reveals that the stiffness, absorbed energy and strain energy density were increased by 32%, 59.2% and 18.02% in filler-loaded composites, whereas the residual dent was reduced from 0.9 to 0.5 mm as compared with baseline. As compared with 3 mm indentation displacement, the % of AE hits related to delamination and fiber failure was significantly reduced to 3.6% and 1% during 6 mm, respectively. Further, the sentry function results that shown very small two P_II functions indicate a better indentation resistance in filler-loaded composites, which were well correlated with rear side photographic images. Besides, the filler-loaded composites exhibited least reduction in the residual compressive strength of 3.71% and 4.33% for 3 mm and 6 mm indented displacements, respectively. However, the microstructural analysis was used to validate the effect of iron fillers on glass/epoxy composites. Finally, this study concludes that the impact resistance of fiberglass composites was greatly improved by the addition of industrial waste iron fillers.