Deformation and failure of a novel fiber-metal hybrid lamina composite under quasi-static and impact loading

Abstract A novel composite comprising two laminae, each integrating fiber and metal within a single layer, is established, with the objective of addressing the common problem of structural degradation via debonding between composite and metals in conventional Fiber-Metal Laminates (FMLs). Each lamina consists of an aluminium sheet with rectangular perforations punched out in a grid-like pattern; basalt roving is then “woven” into the sheet by running parallel strips of roving in one direction through the perforations, alternating above and below of metal segments. This results in interlocking of the roving and metal constituents, and the lamina can be considered an assembly of many small metal-composite interface (MCI) units, where the roving and metal are in mutual contact. Two such laminae are stacked together, and epoxy is infused into them to create a bi-layer composite. Specimens are then subjected to quasi-static and projectile impact tests, to examine the deformation and failure induced. Examination of post-test samples show failure and debonding within only a limited number of MCI units in a lamina, because of the intimate integration and interlocking between the fiber and metal components. Moreover, no debonding between the two adjacent laminae is observed. This indicates that the novel architecture of the composite, endows it with excellent resistance against crack propagation, not only within MCI units, but also within the basalt-reinforced epoxy component. It is envisaged that with appropriate optimization, the mechanical properties of these new fiber-metal composites can be further enhanced and implemented in applications where conventional FMLs encounter limitations.