CRACK SHIELDING MECHANISMS OF INTERLAYERED EPOXY MATERIALS UNDER QUASI-STATIC AND FATIGUE LOADING

This research explores the capability of PEI and PVDF thermoplastic interlayers to arrest cracks in epoxy materials modified with short-glass fibers and core-shell rubber particles. It also investigates the effect of interlayer position, the number of interlayers, and the type of epoxy materials on the fracture performance under mode-I quasi-static fracture and fatigue loading in a single-edge-notch bending configuration. The quasi-static fracture results demonstrate that the thermoplastic-epoxy interface effectively arrests the initial crack and reinitiating the crack at the thermoplastic layer requires up to 2.5 times higher load than the crack initiation load of the pristine epoxies. Furthermore, the interlayered designs exhibit up to 43 times more energy absorption than their pristine counterparts, and the study captures the competing damage mechanisms and failure events using microscopic images, digital image correlation, and high-speed photography observations.