Impact loading on fibre metal laminates

Abstract Static identation and low and high velocity impact tests are conducted on specimens with a circular clamped test area. Monolithic A1 2024-T3 and 7075-T6, various grades of Fibre Metal Laminates (FML), and composites are tested. The energy to create the first crack for FML with aramid and carbon fibres is comparable to fibre reinforced composite materials and is relatively low compared to A1 2034-T3 and FML with R-glass fibres (GLARE). GLARE laminates can show a fibre critical or aluminium critical failure mode. The dent depth after impact of FML is approximately equal to that of the monolothic aluminium alloy. The damage size of FML after impact is considerably smaller than of glass and carbon fibre composite materials. The maximum central deflection during low velocity impact loading is approximately equal to the static deflection at the same energy (i.e., area under load-deflection curve). This deflection can be modelled using the simplified Von Karman equations neglecting the contribution of the in-plane displacements. For these calculations the shape of the specimen under load was measured. This shape was approximately independent of the central deflection and the type of material.

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