Experimental and numerical studies on lateral low-velocity impact behaviour and residual axial strength of circular aluminum alloy (6061-T6) tubes

Aluminum alloy (6061-T6) is commonly used in engineering applications owing to its lightweight, anti-corrosion, and good plasticity, such as the reticular space structure of the Interamerican Exhibition Center of Sao Paulo in Brazil, Sport Hall of Quito in Ecuador and the Memorial Pyramid in La Baie in Canada. Herein, the typical impact process of aluminum alloy (6061-T6) under lateral low-velocity impact were investigated through experiments and simulations. A drop-weight test fixture was used for lateral impact experiments, considering the influence of span length, tube thickness, diameter, impact kinetic energy, impact momentum, and impact po-sition. The plastic deformation and failure modes of the aluminum alloy (6061-T6) specimens subjected to different impact conditions were studied after the experiments. Four types of failure patterns are described ac-cording to the three-hinge mechanism. Quasi-static tensile tests were performed to calibrate the constitutive parameters using the Johnson-Cook model. Meanwhile, a finite element (FE) model of circular aluminum alloy tubes verified the results of the impact test and to analyze the evolution of the dynamic failure. The simulation results were used to analyze the plastic global displacement and energy dissipation. The concepts of both global lateral stiffness and local lateral stiffness were proposed, and two types of energy dissipation modes were described. In addition, the study considered the residual axial strength of the specimens after low-velocity impact. A residual performance model was developed to analyze the effects of span length, wall thickness, and various factors. Finally, a calculation formula was proposed to predict the residual axial strength based on the simulation results.