Inertial stabilization of buckling at high rates of loading and low test temperatures: Implications for dynamic crush resistance of aluminum-alloy-based sandwich plates with lattice core

In the present study, the dynamic compressive behavior of aluminum-alloy-based tetrahedral-core truss structures is investigated as a function of impact velocity using a split Hopkinson pressure bar. The results are used to understand the phenomenon of buckling in truss structures as a function of loading rates and test temperatures, and its implication on the dynamic crush resistance of tetrahedral-truss-based sandwich structures. In order to understand the effects of the flow strength of the core on the dynamic crush resistance, truss structures of both T6 and OA heat-treatments of AA6061 were investigated. A high-speed digital camera was used to record the sequence of the deformation and failure events that occur during the dynamic compression and failure of the truss sub-elements. A buckling instability was observed to occur consistently for both the T6 and OA microstructures at all test temperatures employed in the present study. Moreover, the T6 heat-treatment and the lower-than-room test temperatures significantly increase the specific energy absorption capabilities of the truss structures.