Empty and foam-filled circular aluminium tubes subjected to axial and oblique quasistatic loading

Abstract Tests on tubular columns made of the aluminium alloy 6060-T4 under axial and oblique, quasi-static loading have been performed. The columns were fixed at one extremity, while a concentrated force was applied at the other through a rigid collar. Empty and foam-filled columns were tested for load angles equal to 0, 5, 15 and 30 degrees with respect to the longitudinal direction of the column. The column's outer diameter was 80 mm and the thickness was 1.5 mm, while the distance from the point of load application to the fixed support was 245 mm. The aluminium foam density was about 0.3 g/cm3. The response parameters were the peak force, the absorbed energy and the mean crush force, in addition to visual observations of the deformation mode and fracture. Furthermore, LS-DYNA simulations of the experiments were performed. The columns were modelled with shell elements, while brick elements were used to model the aluminium foam core. The aluminium alloy was modelled using an isotropic elastoplastic model with isotropic strain hardening. Fracture in the aluminium column was not considered in the simulations. The aluminium foam was modelled using the Deshpande-Fleck model. In selected simulations, fracture was assumed to occur at a critical value of the plastic volumetric strain. The agreement between the experimental and predicted results was in general good.