Experimental and numerical study on dynamic behavior of aluminum circular tubes and aluminum foam-filled composite tubes under combined static axial loading and lateral impact

Aluminum alloy circular tubular members in building structures may be subjected to accidental lateral impacts during service, experiencing coupled effects of axial static loading and lateral impact during the damage process. This study presents an experimental and numerical investigation into the dynamic behavior of 6082-T6 aluminum alloy circular tubes and aluminum foam-filled composite tubes under combined static axial loading and lateral impact. A test setup incorporating a self-compensating axial force device was developed to maintain stable axial loading during impact events. Twenty-one specimens were tested under varying axial compression ratios (μ ranging from -0.6 to +0.6) and impact energies (625–5625 J), revealing three distinct failure modes: local dent deformation with overall bending, three-hinge plastic deformation, and cracking near the end. Results demonstrate that axial tension enhances impact resistance, increasing peak impact force and reducing maximum displacement, whereas axial compression exhibits the opposite effect. An implicit-explicit approach (using ANSYS/Implicit and ANSYS/LS-DYNA) was employed and verified against the test data to accurately capture the dynamic responses of both empty tubes and aluminum foam-filled tubes. Parametric studies were also conducted to investigate the influence of filling aluminum foam into empty tubes under various loading conditions. A dimensionless empirical formula was derived to predict the maximum displacements of the tubes subjected to lateral impact (without axial force and under axial compression with μ = -0.4). The findings provide guidelines for the design of aluminum foam-filled composite tubes under combined axial static loading and lateral impact.