Effect of Controlled Local Microstructural Modification of Glass Fiber Epoxy Composites on Progressive Damage Propagation Under Tensile Loading

Abstract

Advanced composite materials are defined by hierarchical, heterogeneous, and anisotropic behavior, resulting in complex, multi-scale progressive damage mechanisms, making failure predictions even under simple loading a challenging task. With the widespread usage of polymer composites for structural applications, holes, notches, and other geometric features are often needed for assembly and other functional requirements necessitating improvements to the local architecture around the holes to alleviate associated stress concentration effects. Multiwalled carbon nanotubes (MW-CNTs) when incorporated with epoxy matrix have shown to increase the open-hole tensile (OHT) strength of unidirectional glass fiber reinforced plastic (UD-GFRP) laminates by altering the inherent damage mechanisms. To assess the incipience of damage in MW-CNT modified UD-GFRP laminates, X-ray microcomputed tomography (CT) of the specimen before and after failure have been carried out in the current work. Future work is ongoing to perform in situ tensile testing assisted with X-ray micro-CT to have a better understanding of damage evolution in the specimens.