Experimental study and finite element analysis on mechanical performance of the steel tube column filled with aluminium foam under eccentric compression

To investigate the compressive deformation mode and flexural mechanical performance of steel tube columns filled with aluminium foam, a series of corresponding experiments under the quasi-static eccentric compressive conditions were performed to obtain the failure deformation diagram, load-deflection curve and load-strain relationship. Based on the experimental study, A finite element model was established to analyze the mechanical performance of steel tube columns filled with aluminum foam under different loading eccentric distances. The results show that the restrained bending deformation was more pronounced in the steel tube column filled with aluminum foam, and this deformation significantly improved the overall mechanical performance as the porosity of the aluminum foam decreased. Compared with the pure steel column, the ultimate loads of the aluminium foam-filled steel tube column with porosities of 90%, 80% and 70% were increased by 87.13%, 93.41%, and 104.11%, respectively. The tensile or compressive strains of the pure steel tube column and that filled with aluminium foam respectively appeared symmetric and asymmetric phenomena because the failure deformation mode of the steel tube column was influenced by filling aluminium foam. Compared with axial compression, the ultimate vertical loads of the aluminium foam-filled steel tube column with loading eccentricities of 30 mm, 50 mm, 100 mm and 150 mm decreased by 48.78%, 60.35%, 80.19% and 88.61%. The steel tube columns filled with aluminium foam under axial compressive action and eccentric load appeared different failure modes, which were respectively the progressive crushing symmetrical deformation and bending deformation. The corresponding failure phenomena of these tubes were observed to transition from local buckling occurring at the loading or fixed end to overall bending deformation along the column length with the gradual increase of eccentricity. Furthermore, the bending moment value of the steel tube column filled with aluminium foam obtained from the experiment under different loading eccentric distances increases with the decrease of load eccentricity.