Quasistatic tensile and flexural behaviors of fiber metal laminates after subjecting to uniaxial tensile impact loading

This study represents a novel contribution regarding the behavior of fiber-metal laminates (FMLs) under tensile impact loading. The experimental program included axial tensile-impact tests and quasi-static tensile and flexural tests after impact. The FMLs' core consisted of an epoxy matrix reinforced with long glass fibers, and their skins had 1050 aluminum plates. Several variables were investigated, including the lay-up methods and the insertion of the [90°] layers within [Al/0°/Al] and [Al/0°/0°/Al] FML specimens. The results showed that the residual tensile load of [Al/0°/90°/0°/Al] sandwich specimens' lay-up method was 6.65 kN, from the original ultimate load of 17.69 kN. For bending after impact, the residual load was 0.79 kN, from the original one of 1.46 kN. Although inserting the [90°] layers provided low tensile strength, it effectively blunted the propagating crack in the load's direction under either the quasi-static tensile or the tensile-impact tests. For progressive damage, the [0°] layer showed fiber breakage and fiber-kinking, and the [90°] layer exhibited critical matrix cracking. Meanwhile, the aluminum plates exhibited a transverse crack during the delamination between the composite core and aluminum plates. During the tensile-impact test, two divisions of delamination were observed: partial delamination aside from [0°] and severe delamination with [90°].