Carbon-fiber aluminum-foam sandwich with short aramid-fiber interfacial toughening

Interfacial toughness and toughening mechanisms of a sandwich beam, consisting of an aluminum foam covered with two carbon-fiber/epoxy composite surface layers, are investigated in this study. To improve the interfacial toughness of the sandwich beam, short aramid fiber of different lengths and densities were inserted at the interface during the sandwich fabrication process. The interfacial toughness between face-sheet and core was then measured through the Double Cantilever Beam test for various sandwich designs. Improvements of varying degrees in the interfacial toughness were observed for all specimens toughened with short aramid fibers of different lengths. The interfacial toughening performance and underlying mechanisms for energy absorption were discussed and analyzed using scanning electron microscopy.