Improvement of energy absorption of expanded metal tubular structures under compressive loads

Herein, several approaches with the aim of improving the crashworthiness performance of expanded metal tubes were assessed experimentally and numerically. In this regard, various expanded metal tubes were produced out of expanded metal sheets including expanded metal tubes, stiffened expanded metal tubes, foam-filled expanded metal tubes and multi-layered expanded metal tubes. Their crashworthiness performance was evaluated under quasi-static axial compressive loading. The effect of cross-sectional type (square and circular) and cell size (large and small) were also evaluated. Results showed the significant effect of cell size on the crashworthiness performance of expanded metal tubes, while the cross-sectional type had negligible effect. Moreover, the energy absorption properties of expanded metal tubes improved through welding expanded metal sheets in the core (stiffened expanded metal tubes), embedding expanded metal tube in foam, and placing several expanded metal tubes concentrically. Among the studied approaches, the foam-filled expanded metal tubes exhibited the most stable compressive load-displacement response, which is desirable for energy dissipation. Furthermore, the load-displacement responses of prepared expanded metal tubes were also predicted acceptably by the proposed finite element modeling. Finally, the effects of expanded metal tube parameters on the crashworthiness performance of tubes were investigated numerically.